Tried clearing the cache. Doesn't seem to matter what computer or browser I try it from, either: Firefox, IE or Chrome. I switch views and five to ten seconds later the numbers change. Always to the same numbers, though. Maybe I'll try unhiding all of my games. Could be something to do with that.

Worth a shot. But that wouldn't explain the three completely different figures though. If two were the same then it would be more likely the case.

not too damn many enough

Indeed.

Well, unhiding the games worked... sort of. Hid some of the games again and the numbers were still right. Hid all the games I hid before and it was back to the same thing. I'd say it's some sort of hard limit on how many hidden games it counts in each sorting mode. "By title" seems to be the only one that is always correct. Point of interest: "by purchase date" was never sorted correctly, even completely unhidden. I had games I bought in 2009 show up lower than games I bought when GOG was starting up...

Did you try an account refresh?

EDIT: You also might try mentioning this issue in the unbundling sticky thread, if you haven't already.

That's a pretty odd bug. Nothing major, I suppose, but it might be worth pointing it out to support.
I've heard of people losing games off their shelf using that thing.

So, looking more carefully, it's not simply a counting error. The limit is 99 hidden games for purchase date and 199 for manual sorting and that is all the hidden games it shows is those modes. It is only in sorting by title that it shows all the games I own.

Wait, so do you mean you're actually missing games from your shelf depending on which sorting method you select, or is it only the number at the top that changes?
EDIT: Never mind, mister ninja.... :)

Yup. I've reported this issue to support with a link to this thread.

This is good. :) And true.