Trying to scroll down the list of games will regularly force the list back to the top. It's an immense pain to try to see who is in a game, or to join one. I think every time a new game is opened, or an old game is closed, the list refreshes and sends you back to the top.
Yeah, it's very annoying. Please fix. It feels like UI control is taken away from you, like the list is fighting to prevent you from seeing its lower reaches (no innuendo intended and any alliteration is only alleged).
This is actually a valid bug. Spectator mode isn't quite up there yet. There are tons of stuff that it still needs and given the serve priorities atm, I'd counsel some more patience or bump to a bug post. Getting back on topic, the simple fix is to refresh queue without resetting the client side scroll position.