It seems like the plug-in isn't working anymore, at least inside a subforum. You can still click on the Subforum's icon and mark everything in it as read, but its not working on individual topics anymore. At least not for me anyway.
This HAS happened before, but it fixed itself after a day or two. This has been going on somewhere between 4-6 days now. Maybe my account tripped some kind of glitch in the forum?
See, I don't think it's actually locking the threads. It just makes it LOOK like we are, even though it doesn't do anything. This has got to be a weird interaction between mods or a problem with the forum code.