ok, then this is probably caused by a bug I've already fixed. The next stable release should work fine
tried a lot of things:
Bake procedural textures
Changed for different HDRI environment
HDRI changed on Corona sky
Hidden geometry curtains
Reset Xform geometry walls and smoothing groups
Turn off all the lights except for the environment
Changed the types of glass on the door (it was thought that some caustic curve of the glass in the door)
And nothing helped, this bug has remained on the walls (
until there is no more any thoughts about possible causes, so that the only hope for you)))
and when will the next stable version? )