Cron Job Error Prevents Proper Content Indexing?

Problem/Motivation

Recently created articles not appearing in search results.

Steps to reproduce

1. Using iFrame extension, create content type with an iFrame field.
2. Specify a URL that is considered invalid by the cron process. In my case, it was file://parsbrown2/c$/inetpub/wwwroot/BMS2021a.html, which I was able to view in a browser but for whatever reason, something in the cron job didn't like it. This file name appeared in errors in the Recent Log Messages report. Here's the full error message.

InvalidArgumentException: The URI 'file://parsbrown2/c$/inetpub/wwwroot/BMS2021a.html' is invalid. You must use a valid URI scheme. Use base: for a path, e.g., to a Drupal file that needs the base path. Do not use this for internal paths controlled by Drupal. in Drupal\Core\Utility\UnroutedUrlAssembler->assemble() (line 65 of /opt/rh/httpd24/root/var/www/html/vistaprd/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php).

3. Run cron from the administration page. Check the Recent Log Messages report for an error.
4. Create a new article with a unique phrase to search for.
5. Re-run cron.
6. Search for the unique phrase. In my case, the new article did not appear in the search results.

Proposed resolution

When I reviewed the report, the above URL appeared in every error listed. I tracked down the article and deleted it. I re-ran cron, searched for the unique phrase in my new article. The article now appeared in the results.

Apparently, indexing stopped when the error occurred. I believe the article with the error should have been skipped and indexing should have continued.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet