WordPress Websites Interacting with Each Other (CPTs and rewrite rules)

Hello,

I’m having a strange problem that I’ll try to explain.

It’s been a few months that I am intermittently getting 404 errors on my custom post type pages until I resave the permalink options.

When my site is experiencing an episode of 404s, I could see the rewrite_rules table is, in fact, missing my CPT’s rewrite rules.

I have been at a loss figuring out what may be causing the rewrite rules to get removed from the database.

Last night, the 404 errors returned once again. Before resolving the issue, I used a plugin (Monkeyman Rewrite Analyzer) to look over the rewrite rules.

What was very peculiar was that instead of my expected custom post type rewrite rules, I noticed that the rewrite rules from a different custom post type from an entirely different website on my server were there instead.

I have no idea how it would be possible for another WordPress installation on my server to be hijacking/overwriting the site’s rewrite rules.

Any ideas as to what could be going on?

David