Hey,
There is material problem in my scene. But this problem is only on mobile device (android). In editor, there is no problem, everything seem normally.
In mobile device, when camera rotating almost 90 degree, the material is be dark a lot of. Images can explain it more.
the tables, bookshelfs vs. seems good but ground, walls and ceiling turn dark.
In Editor Window:
In game on mobile device:
(camera is on same position, it is only rotating.)