Content of first post in threads disappearing

[rant boss]

Version 3.6.8

First posts of threads frequently appear blank after a few days (in other words, the content is there for awhile, then suddenly disappears for good).

It doesn't happen in every thread, but in a decent amount of them. I'm using the Blaze skin -- but don't think that's a problem, because I use it on two different VBul forums, and only have the problem on one of the forums.

Has anyone had this problem, and if so, how did you solve it?

Thanks in advance for your reply.