lightmap problem, overlap uvs

Hello Unreal pals

I have a very weird situation since I am such a Unreal newbie and I can’t solve the problem myself.

When I try to bake my lighting inside of Unreal it keeps giving me this artifact on my ceilings which are single sided

planes, and it keeps telling me that I have a UV overlapping.

I am 100% sure that my plane has 2 different UV channels and the 2nd channel is laid out inside of the grid, also,

I have set my lightmap coordinate to 1, but it still gives me the same error.

Thank you guys, any help will be highly appreciated!