Weird lighting

Lately I'm getting these weird shadows appearing out of nowhere





Notice how the shadow is not pixelated at all, while this wall texture has a a lightmap scale of 16


Anyone knows what could be causing this?

I tried with normal & final and the results are the same.

I should mention that these lighting glitches appeared at a certain point in the development, but I don't know when exactly, so it's probably caused by something in the map than compiling.