Objects not showing on baked AO map

Everything was going OK but decided to change UVs on one part (not the one affected) and suddenly when baking AO map, two objects wont show on AO map when baked.

I did not touch the affected area when redoing UV (it was done on different part)

I even tried to load old file, reexported from blender but the problem persists.

Any idea why when before it was working?