Frequency: Fairly rare
If a player requests a game via the menu while someone is selecting a hero (I believe these have to happen at the same time in order for this bug to happen), the game will softlock itself for the player selecting a new hero. The timer will not tick down for the player selecting the hero (thus you cannot wait the time out), you cannot click “accept” or “decline”, choose a new hero (or confirm), or open the options menu to quit. The only way to leave this state is to force quit the game.
I’ve attached a screenshot with this issue: