When they are far from the player they are moved closer to him, so that shouldn't happen. Did you play the jam version or the updated one? Thanks for playing! I'm glad you liked it :)
The updated one! At some point there were just no more monsters when I respawned (after the 10th time respawning or something) . Dying again didn't fix it to.
I replayed it and this time the bug didn't occur :)