I took another look at my game mode (which I’m not using for anything yet) and noticed it’s still only the constructor.
As a wild hunch, I added a BeginPlay method to see what would happen.
void ACustomGameMode::BeginPlay()
{
}
Even though it contains no code, adding that caused the game state to start ticking. I don’t have a good explanation for that, aside from a vague knowledge that those two classes are closely related.
Even weirder is that after removing ACustomGameMode::BeginPlay(), the GameState still ticks. I especially can’t explain that one.