Lightmap baking error

When i try bake lightmap o got next error:
Assertion failed on expression: ‘terrainInstanceHashes.find(instances*.instanceID) != terrainInstanceHashes.end()’*
how fix it?
Unity 2018.3.14.f1

same on 2018.4.1f1. help?

same issue here. Using unity 2018.3.9f1