Terrain lightmap looks corrupted on the working device

Only one of 4 game scenes became suddenly corrupted with terrain lightmap.
In editor & Emulator everything looks fine. On real device - bad (Android 8.1.0 device).

Unity version 2019.2.15f1. Everything worked fine for a long time. Yesterday I really did only a few minor changes in the game scene and here is the result (i just added a few objects on the scene). I have no idea why does it happen & how to fix it. Any help?

Here are some screenshots from the real device. Green color - normal terrain texture. White, blue and bloody red - corrupted parts. It appears only on the real android device.

Any ideas why it is happening? Maybe some standart solutions for this?