Just found a second glitch in the same place as above... Hopefully, I don't get in trouble for double posting about two separate subjects here.
In the Zhentarim Hideout at X: 281 Y: -180, while you are on the downward slope right in front of the cell gate, the wolf right above you disappears. Further, the roaming guard will also seemingly become invisible while moving up the slope or in the area right above you. And I'm not meaning they're on another ledge or simply hidden behind something. From a different position they can be seen easily, but while you're in that one spot in front of the door they remain invisible. Though you can still hover over them with the cursor to get a kind of white outline of them.
Spooked the hell out of me when I seemingly got caught stealing by a ghost.
And the monkey flips the switch. - A former Field Artillery Sergeant