Destructible mesh became too bright

Hi. My first problem was that when I built light a mesh next to the destrucible one became complety dark. I solved the problem by

making lightmap resolution of that mesh to be 512, and changing the Light Map Coordinate Index to 1.
I built light again, it became normal but my destructible one become extremely bright

229252-mesh.png

Please help!

Now I covered the destructible mesh with a box and it became dark

Help please!