Hi!
It should not cause a problem (different rotation) if you have high enough lightmap resolution or enough padding between the uv islands!
Looking at your lightmap uvs… could you explain to me please how can it has 16 faces? …even if you’ve kept all the faces and these are just 2 boxes snapped together it’s all together 12 faces…
But you can be kind of sure: if you have completely black faces after build, those faces don’t have lightmap uv assigned to them, they can’t visualise lighting information…
…if it’s not completely black it can be reflection problem too…
So let’s just stick to this one object!
How is it mmodelled? How many faces does it have? Any overlapping parts?
What is your padding at the sides and between the islands?
What is your lightmap resolution?