Sometimes, NPCs (all without a key) get stuck in a locked room; likely got locked in when the previously opened otherwise-locked door automatically closed by itself.
Not sure if this is WAD but, after loading a game, a red debris thingy appeared on spots where NPCs were killed. A quick searches on this Discord seem to vaguely suggest this is something from ButlerBot?
Sometimes, areas failed to load and are all black; seem to be worse if you go to the mainland, especially in larger cities like the "national" capital. Reloading fixed that.
Lags when going to the second floor of the City Hall; persists even after I made all dead NPCs disappear with punching their corpses, possibly indicating it is not the number of NPCs that is the cause of the lag?
On one occasion, I had a shopkeeper in what is clearly a weapons shop (marked as such on the map) actually selling groceries.
I don't know if this counts as a bug, but a particular variation of a restaurant building lot has NO refrigerator in it (???). Probably an oversight.
The corner of a building intersecting with a fence is sometimes wonky.
Sometimes, there is a double door object in what is clearly a single-block opening. This is seen in a variation of an employment center building lot.
Sometimes, windows disappeared. Happened at least once at my home base.
Sometimes, a shopkeeper, when killed, is never replaced, which could be a real problem, especially if their shop is the only shop of its kind on the home island...
On one occasion, a car I bought from a car shop was spawned in an inconvenient location, which is an area between the fences and building wall. I was able to get the car out, though.
Occasionally, sign objects are invisible but still solid.
Perhaps a bug, nonetheless amusing, in that a slum dweller was once found sleeping on the shop display table in an empty store (no shopkeeper / clerk to be found anywhere at that time).