Just did that quest and noticed a couple things. The key to the door doesn't age on carpet, which makes it far easier to storm through the quest if your clan has one.
The grolms should probably be modified so that someone with 151 perception and no light cant ninja through as well. Grolms adapted to sea living probably wouldn't have the same sort of sensory organs after all.
Also, about one in ten Sea Grolms dropped a tit axe and they are considered magical on grave inspection. Seems wrong!

It had the Age on Carpet flag set so it should have aged on the non expire carpet, unless I have found the wrong key.
I have also set the Age Offline flag as well.

About half of them have been given Infrared vision so they should now be happy living in the gloom (and hunting you).

I have turned off the Magic flag on the axe. I am not sure why it was turned on in the first place.
The Sea Grolms are set so that they do not always drop a grave. This was because it was filling the world with huge amounts of tit axes which in turn lead to masses amount of gold from the sea.

See if this fixes it.

Aging on the ground seems much more lenient from what I remember last playing, which is what tripped me up there but looks good otherwise.
The axe being magic was weird for sure and probably some weird vestige of their worth in v2. I haven't checked but am pretty sure sell prices have changed since vanilla. Weapons and potions give a lot less, while rings stand out as the meta for efficient gold farming.
I vaguely recall an area in CQ that lent itself to garnering a fortune from the weapons and close merchant, which may have tipped someone off to looking at pricing.