We are running V6.4.4. We don't have phpMyAdmin on the server. Badwords filter is enabled but hasn't been touched in months (we just have your basic cuss words in the filter).
Josh, the problem is there whether we search and view or just regular browsing and reading of threads.
I'm almost convinced this user deleted all of his threads - but it turns out he had over 2100 posts, and I can't believe someone would do that. No other users are affected. I tried repairing all relevant tables and no change.
Board url is
http://www.4x4wire.com/forums/categories.php?Cat= and the username is thief.
Thanks for your help with this.