In game I am spawning 11 bullets every second and a new enemy every 2 s. The bullets are staying on screen, and the enemies I killed immediately. Thus everything should be the same layer/mask for most of the time, but collision pairs still increases, seemingly exponentially.
Why is that? Why doesn't killing an enemy decrease the number of collision pairs more (especially since there is typically only 1 enemy on the screen at a time)?
For example, the following screen shot has 27.5k collision pairs, 26 fps, 3.1k nodes and 4k objects, but nothing has colliding layers/masks (the red stuff is not colliding). Why could that be?