can you fix these 2 abyss bugs - it's overdue....

1) pits that don't spawn the 'last wave' of monsters with the rare monsters, but remain open and the quest on the map for abyss remains unfinished

maybe it is due to monsters that hide in the ground or I don't know... I have walked around these pits so much and couldn't find a missing monster to get the pit to spawn the wave,
it happens over and over again - randomly, but mostly I encountered it in the map 'steppe'

Edit: In my mind, a fix could be that, whenever a player stays around the pit for a certain amount of time (has to be some kind of acceptable radius, not just a very small one)
then the pit will automaticly spawn the rare monsters, unlike the situation we have now, where you need to kill a whole bunch of monsters to get the abyss to spawn from the pit
and also - the essence monsters and other types are also required to kill to spawn the abyss from pits when they are in range, I find this kind of strange and I'd rather not that be the case...

2) Abyss monsters not taking damage for whatever reason, mostly it is the snake-like creature that jumps into the ground and does some kind of sweep attack with their tail,
I often encounter them and try to hit them over and over, it just won't happen, until randomly it will happen and they die...they can't just have like a million evasion to evade all attacks...