Hundreds of new anonymous contacts created by theme files

Mautic version is: v4.4.4
PHP version is: PHP Version 7.x.x
Database type and version is: mysql 8.0.x
Running Mautic v4 in a container behind a reverse proxy

Summary: We’re seeing a significant delay when editing and saving certain email templates and hundreds of new anonymous contacts being created per day with IP address of (localhost) even though our reverse proxy setup appears to be working fine.

Details: On a new installation of Mautic we imported a custom theme that we privately developed for an older version of Mautic and have been using it to build emails. We were able to use the theme with grapejs by adding "builder": ["legacy", "grapesjsbuilder"] to the theme config.json file. Now we’re seeing hundreds of new anonymous contacts being created per day with IP of The contacts are always created by page hits to the same theme asset files (font files that were packaged as part of the custom theme). We are also seeing anonymous contacts with legitimate-looking IP addresses so we believe that the X-Forwarded-For is being passed by the reverse proxy and detected properly by Mautic. For non-anonymous contacts, the Mautic event tracking appears to be working as expected except that we see the line - Accessed from IP in some places in the event logs. There are no errors shown in the logs. However, we have also noticed a significant, but sporadic delay when trying to edit or save certain email templates that use our custom theme. It’s unclear to us whether this is one issue or multiple separate issues but the anonymous localhost contacts always seem to be created while someone is working on an email template.

Has anyone seen an issue like this? Could anyone provide guidance on how to debug this issue?