[Voobly issue] Kicked by anticheat for minimizing in lobby?

A few friends and I recently made the switch from HD to Voobly but we're having this weird issue that if someone minimizes in the pre-game lobby (in-game) they get detected by the anticheat and banned for 15 minutes. They don't use AutoHotkey or anything like that, what's going on?

I know the obvious workaround of not minimizing but sometimes someone forgets and then we have to wait 15 minutes for them to be able to join again, and I'm worried someone is going to get a permaban if they forget enough times.