At the moment I can't really go and disable all the plugins without knowing which one is causing the issue, we have a fairly large user base (over 30k) and they'd get pretty annoyed with losing any features they really like. I've disabled a few more today and waiting on a response on if the issue is still happening or not (as it doesn't happen with all pm's just seems to happen randomly though).
The products we currently have installed are the following (and I do know there are quite a few, they were installed before I got proper access in the admincp):
- AdminCP Top 10 Statistic
- Competitions
- Cyb - PayPal Donate (*)
- Delete Post when Giving Infraction
- e-steki Referrer Statistics
- IpInfo (*)
- Quick Reply Thread Management
- Real ip detection
- Split Useronline
- vB Ad Management (*)
- vRules
The ones with a (*) after are the ones I know for certain are outdated versions and as such will also be getting those upgraded over the next day or two to make sure that isn't causing the issue.
We also have three plugins that aren't linked to any of those products and two of which are custom ones we created to show extra info in our header (avatar and the other just runs a query to grab some info). The final extra plugin is used to show custom status icons for the forums.
If anyone has experienced any similar problems and knows if any of the above products are cauisng it then I'd appreciate being told. Otherwise I'll try disabling a few more of the above mentioned products and reporting back once that is done.