Search API Solr Multisite: No Results When Enabling “Rendered HTML Output” Field

Setup

• Solr version: 7.7.1
• Drupal Core version: 10.2.6
• Search API version: 1.34
• Search API Solr version: 4.3.3

Issue

I am experiencing an issue with Search API on a multisite setup in Drupal 10.2.6. As soon as I enable the "Rendered HTML output" field in the index, my search results return nothing. I need to use "Rendered HTML output" because a significant number of paragraphs are not being indexed without it.

I tried to troubleshoot the problem by examining the $datasource_id values at https://git.drupalcode.org/project/search_api/-/blob/8.x-1.x/src/Entity/...

• When $datasource_id is set to 260ojw--entity:node, I receive the following error:
  
  

  The datasource with ID '260ojw--entity:node' could not be retrieved for index 'Content'.

• When $datasource_id is set to entity:node or entity:media, everything works fine, and search results are returned as expected.

I've tried various solutions from other related threads, including:

• Search API Solr Issue #3218868 🐛 The datasource with ID ... could not be retrieved for index Fixed
• Search API Solr Issue #2875916 →

Unfortunately, none of these have resolved the issue for me.

Expected Behavior: Enabling the "Rendered HTML output" field should not break search functionality, and all paragraphs should be properly indexed.

Actual Behavior: Enabling "Rendered HTML output" causes search results to return nothing, and an error occurs when using a specific $datasource_id.

Steps to Reproduce:

1. Set up a multisite environment even with the latest Drupal 10.3.2 and Search API 1.35.
2. Enable the "Rendered HTML output" field in the index.
3. Attempt to search content and observe the lack of results.
4. Check the error logs for issues related to $datasource_id.

Any guidance or suggestions to resolve this issue would be greatly appreciated.