Problem with Baking (strong shadows where it shouldn't be)

Hi.
Before baking the texture, you need to:
- get rid of n-gons;
- split sharp edges;
- preferably get better uv layout.

- select everything with A, Clear seam;
- select those 6 n-gons in Face mode, Mark seam;
- switch to the side view, disable Limit selection to visible, press B, select the back side of the wall attachments. Press Shift H to isolate them. Select everything with A, Select - Select boundary loops, Mark seam, Alt H to unhide;
- delete those areas that are attached to the shelves, they are not visible and not needed at all;
- select one edge marked as seam, Select - select similar - seam, Mesh - edges - edge split;
- in the side view break the uv islands of those wall attachments by marking seams like in the last pic;

- once all seams are marked, select everything and Mesh - Faces - Triangulate;
- with everything selected press Unwrap. Usually the result is ok but not this time, so I suggest you to just select some uv islands, rotate them, and make all of them bigger;