Many times when walking through certain expeditions, mobs start to crawl out of the floor (as a spawn animation i suppose) or their spawn needs to be triggered by walking past them.
This is kind of annoying as i dont want to need to move backwards every few seconds.
Either put the range the player has to be next to them for them to spawn higher (like 20-30m) or simply let the mobs already be on the map without the player needing to trigger their spawn.