Cannot edit blocks in Layout Builder

Problem/Motivation

Using Drupal 10.3.5. Layout Builder 10.3.5. (I don't see this version in the version selector so I just picked the top one)

Nothing happens when I click the pencil icon to edit blocks inside sections inside the Layout Builder. I looked at Console expecting to see JavaScript errors. All it says is "App is embedded in a cross-origin frame. Register as a service worker". I don't know how that would matter for this, but maybe that's the issue.

Steps to reproduce

On a Basic Page, click Edit. Go to Layout. Create a block inside a Section. Hover over the block until there is a pencil icon. Click the icon. For me, nothing happens regardless of the type of block.

Interesting tidbit: It says I have unsaved changes even though I have saved previous changes.

I don't know how to troubleshoot this issue, so I created this as a support request.