AJAX Error, Form Mistakenly Retrieves Full HTML

I haven't run into this issue, nor have I heard of anyone else running into it. Can you share your webform config with me to see if I can reproduce it on a vanilla install? Also, it'd be good to know what version of Drupal you are running and what version of PHP is installed on your server.

The webform config can be found at /admin/structure/webform/manage/webform_machine_name/export or admin->structure->webform->export. You should be able to copy the YML and share it here without sharing any sensitive information.

You can see the versions of PHP and Drupal you are using by going to /admin/reports/status or admin->reports->status report.

Thanks so much for taking a look at this. You'll probably see this in the config, but these webforms are displayed as cards.

langcode: en
status: open
dependencies:
  module:
    - webformautosave
third_party_settings:
  webformautosave:
    auto_save: true
    auto_save_time: 500
    optimistic_locking: false
weight: 0
open: null
close: null
uid: 6
template: false
archive: false
id: intercept_event_feedback
title: 'Intercept Event Feedback'
description: ''
categories: {  }
elements: |-
  step_1:
    '#type': webform_card
    '#title': 'Step 1'
    '#title_display': none
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    '#next_button_label': 'Next >'
    how_did_the_event_go:
      '#type': webform_image_select
      '#title': 'How’d the event go?'
      '#title_display': before
      '#images':
        Like:
          text: Like
          src: 'https://richlandlibrary.lndo.site/modules/contrib/intercept/modules/intercept_event/img/like.svg'
        Dislike:
          text: Dislike
          src: 'https://richlandlibrary.lndo.site/modules/contrib/intercept/modules/intercept_event/img/dislike.svg'
      '#required': true
      '#attributes':
        class:
          - browser-default
  step_2_positive:
    '#type': webform_card
    '#title': 'Step 2 Positive'
    '#title_display': none
    '#states':
      visible:
        ':input[name="how_did_the_event_go"]':
          value: Like
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    '#next_button_label': 'Next >'
    terms:
      '#type': checkboxes
      '#title': Terms
      '#title_display': none
      '#options':
        'learned something new': 'learned something new'
        'fun or engaging': 'fun or engaging'
        inclusive: inclusive
        'empowering or inspiring': 'empowering or inspiring'
        'made connections to my community': 'made connections to my community'
    tell_us_more_positive:
      '#type': textarea
      '#title': 'Tell us more...'
  step_2a_negative:
    '#type': webform_card
    '#title': 'Step 2A Negative'
    '#title_display': none
    '#states':
      visible:
        ':input[name="how_did_the_event_go"]':
          value: Dislike
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    '#next_button_label': 'Next >'
    tell_us_more_negative:
      '#type': textarea
      '#title': 'Tell us why...'
  step_2b_negative:
    '#type': webform_card
    '#title': 'Step 2B Negative'
    '#title_display': none
    '#states':
      visible:
        ':input[name="how_did_the_event_go"]':
          value: Dislike
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    '#next_button_label': 'Next >'
    contacted_by_a_staff_member_to_discuss:
      '#type': radios
      '#title': 'Would you like to be contacted by a staff member to discuss your experience?'
      '#options': yes_no
  step_3:
    '#type': webform_card
    '#title': 'Step 3'
    '#title_display': none
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    '#next_button_label': 'Next >'
    how_likely_are_you_to_recommend_this_event_to_a_friend:
      '#type': radios
      '#title': 'How likely are you to recommend this event to a friend?'
      '#description': '<p>10 = extremely likely, 1 = not likely at all</p>'
      '#options': likert_ten_scale
  step_4:
    '#type': webform_card
    '#title': 'Step 4'
    '#title_display': none
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    '#next_button_label': Save
    how_did_you_hear_about_this_event:
      '#type': webform_radios_other
      '#title': 'How did you hear about this event?'
      '#options':
        'Search engine (Google, Bing, etc.)': 'Search engine (Google, Bing, etc.)'
        'Social media (Facebook, Instagram, Twitter, etc.)': 'Social media (Facebook, Instagram, Twitter, etc.)'
        "Library's home page": "Library's home page"
        "Library's events page": "Library's events page"
        'Blog post': 'Blog post'
        'Through a friend': 'Through a friend'
  step_5:
    '#type': webform_card
    '#title': 'Step 5'
    '#title_display': none
    '#title_tag': ''
    '#prev_button_label': '< Previous'
    confirmation_text:
      '#type': webform_markup
      '#markup': '<p>Thank you for your feedback on this event!</p>'
css: ''
javascript: ''
settings:
  ajax: true
  ajax_scroll_top: ''
  ajax_progress_type: ''
  ajax_effect: none
  ajax_speed: null
  page: true
  page_submit_path: ''
  page_confirm_path: ''
  page_theme_name: ''
  form_title: source_entity_webform
  form_submit_once: false
  form_open_message: ''
  form_close_message: ''
  form_exception_message: ''
  form_previous_submissions: false
  form_confidential: false
  form_confidential_message: ''
  form_disable_remote_addr: true
  form_convert_anonymous: false
  form_prepopulate: true
  form_prepopulate_source_entity: true
  form_prepopulate_source_entity_required: false
  form_prepopulate_source_entity_type: node
  form_unsaved: false
  form_disable_back: false
  form_submit_back: false
  form_disable_autocomplete: false
  form_novalidate: false
  form_disable_inline_errors: false
  form_required: false
  form_autofocus: false
  form_details_toggle: false
  form_reset: false
  form_access_denied: message
  form_access_denied_title: ''
  form_access_denied_message: '<p>Access to this form is currently disabled.</p>'
  form_access_denied_attributes: {  }
  form_file_limit: ''
  form_attributes:
    class:
      - evaluation
  form_method: ''
  form_action: ''
  share: false
  share_node: false
  share_theme_name: ''
  share_title: true
  share_page_body_attributes: {  }
  submission_label: ''
  submission_exception_message: ''
  submission_locked_message: ''
  submission_log: true
  submission_excluded_elements: {  }
  submission_exclude_empty: false
  submission_exclude_empty_checkbox: false
  submission_views: {  }
  submission_views_replace: {  }
  submission_user_columns: {  }
  submission_user_duplicate: false
  submission_access_denied: default
  submission_access_denied_title: ''
  submission_access_denied_message: ''
  submission_access_denied_attributes: {  }
  previous_submission_message: ''
  previous_submissions_message: ''
  autofill: false
  autofill_message: ''
  autofill_excluded_elements: {  }
  wizard_progress_bar: false
  wizard_progress_pages: false
  wizard_progress_percentage: false
  wizard_progress_link: false
  wizard_progress_states: false
  wizard_start_label: ''
  wizard_preview_link: false
  wizard_confirmation: true
  wizard_confirmation_label: ''
  wizard_auto_forward: true
  wizard_auto_forward_hide_next_button: true
  wizard_keyboard: true
  wizard_track: ''
  wizard_prev_button_label: ''
  wizard_next_button_label: ''
  wizard_toggle: false
  wizard_toggle_show_label: ''
  wizard_toggle_hide_label: ''
  wizard_page_type: container
  wizard_page_title_tag: h2
  preview: 0
  preview_label: ''
  preview_title: ''
  preview_message: ''
  preview_attributes: {  }
  preview_excluded_elements: {  }
  preview_exclude_empty: true
  preview_exclude_empty_checkbox: false
  draft: all
  draft_multiple: false
  draft_auto_save: true
  draft_saved_message: ''
  draft_loaded_message: '[none]'
  draft_pending_single_message: ''
  draft_pending_multiple_message: ''
  confirmation_type: none
  confirmation_url: ''
  confirmation_title: ''
  confirmation_message: '<p>Thanks for your feedback on this event!</p>'
  confirmation_attributes: {  }
  confirmation_back: false
  confirmation_back_label: ''
  confirmation_back_attributes: {  }
  confirmation_exclude_query: false
  confirmation_exclude_token: false
  confirmation_update: false
  limit_total: null
  limit_total_interval: null
  limit_total_message: ''
  limit_total_unique: false
  limit_user: null
  limit_user_interval: null
  limit_user_message: ''
  limit_user_unique: false
  entity_limit_total: null
  entity_limit_total_interval: null
  entity_limit_user: null
  entity_limit_user_interval: null
  purge: draft
  purge_days: 182
  results_disabled: false
  results_disabled_ignore: false
  results_customize: false
  token_view: false
  token_update: false
  token_delete: false
  serial_disabled: false
access:
  create:
    roles:
      - anonymous
      - authenticated
    users: {  }
    permissions: {  }
  view_any:
    roles: {  }
    users: {  }
    permissions: {  }
  update_any:
    roles: {  }
    users: {  }
    permissions: {  }
  delete_any:
    roles: {  }
    users: {  }
    permissions: {  }
  purge_any:
    roles: {  }
    users: {  }
    permissions: {  }
  view_own:
    roles: {  }
    users: {  }
    permissions: {  }
  update_own:
    roles: {  }
    users: {  }
    permissions: {  }
  delete_own:
    roles: {  }
    users: {  }
    permissions: {  }
  administer:
    roles: {  }
    users: {  }
    permissions: {  }
  test:
    roles: {  }
    users: {  }
    permissions: {  }
  configuration:
    roles: {  }
    users: {  }
    permissions: {  }
handlers:
  email_if_customer_wants_to_be_contacted:
    id: email
    handler_id: email_if_customer_wants_to_be_contacted
    label: 'Email if customer wants to be contacted'
    notes: ''
    status: true
    conditions:
      enabled:
        ':input[name="contacted_by_a_staff_member_to_discuss"]':
          value: 'Yes'
    weight: 0
    settings:
      states:
        - completed
      to_mail: EventsandExperience_mg@richlandlibrary.com
      to_options: {  }
      bcc_mail: ''
      bcc_options: {  }
      cc_mail: ''
      cc_options: {  }
      from_mail: _default
      from_options: {  }
      from_name: _default
      reply_to: ''
      return_path: ''
      sender_mail: ''
      sender_name: ''
      subject: _default
      body: _default
      excluded_elements: {  }
      ignore_access: false
      exclude_empty: true
      exclude_empty_checkbox: false
      exclude_attachments: false
      html: true
      attachments: false
      twig: false
      theme_name: ''
      parameters: {  }
      debug: false
variants: {  }

Drupal version: 10.1.7
PHP version: 8.1.18

I'm still unsure what was causing this issue but perhaps due to the recent upgrade to Drupal 10.2.2, I'm no longer experiencing this issue so I'll mark it as closed. Thanks.