I have a file with about 12 errors that start with: class net.darkhax.wawla.engine.waila.EntityProvider, i'm not sure which mod specifically it's pointing to but wawla is mentioned in the opening line.
WailaErrorOutput.txt

This issue is caused by looking at an entity that has not been properly registered with the game. 1.12.2 is no longer supported or receiving updates, but you can disable the debugEntities option in the config to disable this code.