Originally Posted by Seren

This is intended behavior. Idle server mode is not meant to be a special "spectator mode 2" available only to hosts. It is a mode intended for servers whose maintainers are not at the keyboard, might never be at the keyboard and, in fact, there might be no keyboard. Much like cooba's messages indicate, ideally, the game window would display nothing or next to nothing in idle server mode, since - in the scenarios it's intended for - there is nobody to display anything for (and sometimes no screen to display it on) and it's a waste of CPU cycles. So yes, spectating in idle server mode sucks; we discourage it, do not intend to improve it, and instead might intentionally make it even worse or impossible in the future. If you want to spectate the game, you should enable spectator mode.

When idle server mode is off, there is indeed a level end screen displayed to the host, because in that case the host is assumed to be at the keyboard and potentially happy to see that screen, like all other players. If the host is not at the keyboard, they should activate idle server mode - as explained above, that's exactly what it's for. If the host is unhappy to see the transition screen, they can press fire to skip it, like other players. Because of the way level transition actions are ordered, the server only sends the clients information about the next level once that transition screen expires, so in the remaining situation that the host is in fact at the keyboard and happy to watch the screen display the winners of the most recent game, everyone has to wait for it to finish. This is the one place where the behavior may be possible to improve. However, odds are, there's a lot of room for things breaking if clients enter a level before the server does, so it's a scary portion of the code to mess with, for limited benefit.