Although I don't know what bugs they are, I have a lot of problems with Window Update. I think the window manager of OS 9.2 has problems, Contextual Manager has too. The update of 9.2 will available from Apple soon I think.
I took it completely off my system cause I thought it sucked. Apparently it slows down you system keeping a constant cache of system activities (maybe for apples "research") which can't be turned off or thrown out.