When at least 3 players are on a map - 2 hit g to ready (not warmup - but ready to start the map) the countdown starts - when the 2 leave the countdown disappears and the "hit g to ready" comes back in - when the last player then hits g to start the map nothing happends
got that on grey stone plaza
I've noticed this most on one map... (ah, bad memory) maybe called Nimbus Ruins? When whomever started the map leaves and someone takes over, no amount of pressing g will ever start the game. I've seen this today (June 20th). I'm pretty sure I've seen this on other maps randomly, but this specific scenario is a reliable bug on that specific map.
Received a bug very similar to this in recent days. Up voted :-)