AR4404 was probably an omission - I don't know what the OE area number is so I can't doublecheck. The 'wrong' lighting in Baldur's Gate was obvious when you got into the relevant areas e.g. NPCs displaying as if they were in deep shadows when they were actually standing under a bright light. It was a long time ago but IIRC it was the sewers that set me off on the correction trail. The lighting on the NPCs and party in many areas of the sewers bore absolutely no resemblance to the ambient lighting e.g. NPCs being coloured purple when standing in a 'green light' part of the sewers. When I started looking at the original lightmaps and comparing them to the areas they represented it was (pardon the pun) blindingly obvious which ones were wrong.
Again, if I was to make a guess, much of the city of Baldur's Gate displays signs of being caught in the release crunch and so had less care taken over it than all of the other major areas. It's only a guess, mind.
-Y-