Welcome to TWC.
Looks like you didn't install the MOS 1.70 all inclusive patch, which switches the Cair Andros settlement for a standard Castle. It solves a lot of other problems too. You can download this patch in the first post of this thread, look for this part:
Massive Overhaul Submod (MOS) 1.7 full version install and download instructions:
It's a pity you seem to have missed this patch, which was released in 2015 IIRC. But it is never too late to fix a game!