No, I haven't restored from a backup. I've done an integretiy check with mysiamchk which reports no problems at all. It's just that the exact same problem occurs on an old copy of the database which I use to insert hacks to the code before I add them to the production site. The testing site, where I do all my hacking, works perfectly fine -- the showthread/showflat scripts are exactly the same on it, the databases are on the same database server and the tables should be the same except for the amount of data in them. Very strange indeed.
