deleted post issue

My moderators brought to my attention that some of there posts were deleted or at least removed. I looked into this further, and found that it has happened more often then I though to a number of members. I know it was not a moderator that deleted the posts, so we are thinking it is an issue with the forum itself.
The forum is working fine at this point only issue is the deleted posts for no reasons. Any help on this issue would be great thanks.

You can check to AC-P => General => Forum --> Security see the Last actions by Moderation.

I have and the post that were deleted did not show up in that area. I know that it was not the moderators that did this. In fact one of my moderators, posted 2 times shut logged out and then back in and both posts were gone. It is not happening a lot but it is happening. I am a sure it is just a glitch of some kind just hope it does not get worse and trying to see if there is something more I can do to fix this.

Was it a post or a whole thread?

just individual posts randomly