You're correct, a lot of people appeared to have lost a lot of posts during a recent maintenance run specifically intended to correct the post count problem. (Most didn't know there was a problem, but there was.) I lost around 900 posts myself. However, everyone can rest assured not one actual post was deleted, it was only the post count that changed.
The reason for the loss was due to the fact that posts in the Gun Show and a few other forums are not added to a member's post count. It has been that way for several years. The post count is intended to reflect only posts in the main forums of TFL. A member can post 1,000 times in the Gun Show without one single contributing post in the other forums. Their post count should be 0. However, some of those posts made it into the post count. The post count correction was made because of that.
All posts counts are correct as they now stand. No posts in any buy/sell/trade forum, in Tech Support, or in the Testing forum are added to a member's post count.