The game timer currently starts counting down while the world isn't yet generated and players are in the lobby. It'd make more sense for it to start the moment players can start moving and breaking blocks.

Fixed in 86ca12e

The timer is reset back to 0 the moment the game starts so this is irrelevant. Don't close the issue tho, as neun seems not to be tracking that this needs to be fixed, as the times should not be shown (or kept at 0) before the game starts.

Do you mean the keeping progress of gametime which counts up?
That's being reset once the game starts, the counting during setup is a display bug (I do use a worldborder timer for a different purpose there and currently that's displayed there as well)

I am just going to assume above is what you mean and this will be used to track that issue. If there is another bug, feel free to open another issue.

The timer is reset back to 0 the moment the game starts so this is irrelevant.

I did not realize that, though it does make sense. Still, it was rather confusing to see it tick up. Feel free to rename the issue title to better describe what the intended behavior is.