u6: seems like a bug with spider webs?

[Konaki]

I'm using Nuvie 0.5 with GoG Ultima 6.

First inside the spider cave, I cannot seem to destroy spider webs created/shot by spiders.
I can solo each character out eventually or use Move for the same purpose, but as more spiders spawn, they spit out more webs into the remaining spaces.

Then once outside the cave (at night), we encountered more spiders, that covered the cave entrance in spider webs. Now the cave cannot be entered anymore and these webs don't despawn.

See the image below:

Is there a specific way, item or spell that is supposed to do this, or is this a bug?

[jkoudys]

Definitely not a problem in the original game. Spider cave is where I'd go to stock up on meat.