Thanks for that, just changed how the Doctors will despawn. The fix won't be released until the next update though. That sounds like a tAPI issue rather than something with the mod - I'll ask about it on the tAPI thread. It'll be something to do with networking code. I'll look into it. There's practically no 1x1 sprites left now anyway, but I'll convert those that remain to 2x2 for the next update. Thanks!