Have you used any save game editors... any?

No I have not.

I am not using any mods either.

Does that mean you don't have any fix packs installed either?

I have exactly the same thing happen.

What I do is kill the hobgoblins and go back to the Friendly Arm Inn and sell my stuff, but hang on to the ring. Then I go back to Joia and give her back her ring. When I exit, the map is fine.

I think it is a bug, and for some reason, it loads the map from the last autosave. I have not tested this theory and it is really a guess on my part.

I don't know if I have any fix packs installed, I have the game as it is configured from GoG :) That is interesting!

Well, as I have done the quests there, I think I'll go and explore the map again, won't take long after all :P

I played BG 1 with no fixes or mods either, direct from GOG. The main bug I noticed was that when u enter caves, ur party order often gets messed up. This can put ur vulnerable spellcasters in a bad position. Thankfully none of the caves where u get attacked immediately held anything particularly dangerous, so u can adjust accordingly.

This is not a "bug", it is purposefully implemented to allow for "surprise attacks" against the party - the people in the front get shifted to the back and the people in the back get shifted to the front. Same thing with area transition random encounters in BG2 - you are *always* attacked from the rear. So it's meant to simulate an "ambush".

Simply change party order before making such moves, and change back after making such moves. Consider it "taking precautions" when you are vulnerable *to* surprise attacks and ambushes...