Why I'm Having These Weird Shadows?

Hi there,
after light build (High Quality) i’m getting weird shadows! is it because of my mesh’s smoothing groups?
*the edge is chamfered (not a hard edge) for the selected object
*i didn’t override lightmass value for the selected object, but i did it for the walls and floor.

thank you for your reply, i’ll check it out.

Artifacts of overlapping UV’s and low resolution lightmaps combination. First make sure those meshes have no overlapping lightmap UV’s, then increase the lightmap resolution. The default value is too low for such meshes(walls, ceilings, floors, etc.)