Shadows problem after building the light

Hi guys!!!

I’m found this problem for a few days ago, and i don’t know what may cause this problem with the shadows.

I’m doing an interior for architecture visualization, but after building the lighting the shadow goes crazy on some faces because the turn slightly darker and purple.

I increased the light map resolution and change to Detail lightning mode and everything seems to be good, but after building the light a have the same problem with the purple faces…

Please let me know if i’m missing anything, i’m leaning to use UE and i love it. And a want to learn everything to reach the realism of unreal engine.

Really appreciate the help and thanks for the attention.

Me too,but i don’t know why,418 it is ok

Thank you, i’ll try it in 4.18 i hope that can solve my problem.