East/West facing white windows appear gray

[Alpacku]

1.67.45.1020

All DLC except Batuu
No mods or CC. 

Interior of East/West facing white windows appear gray

interior of North/South facing windows appear normal.

I have up to date video drivers and have tried resetting the game and cache. 
Bulldozing the lot does not fix this issue. 
I would assume this is a common issue but have been unable to find bug reports or similar, assuming some sort of hardware problem or sims 4 being strange as usual.