Hi!
Meshes are calculated separately during light build! What you see here is shading differences! You can tune your lightmass settings to get rid of those: set 0.15 for scale and 0.6 for smoothess and they will be gone! 
Hi!
Meshes are calculated separately during light build! What you see here is shading differences! You can tune your lightmass settings to get rid of those: set 0.15 for scale and 0.6 for smoothess and they will be gone!