Lightmass issues in 4.20.3

Hello all
Are there any known erros with the lighmapping in 4.20.3 ? as i cannot properly bake lighting in this engine version.
Black spots, black objects appear every time after the baking process ends.
There is no such problem in the earlier version (4.19) and also in the newest 4.21 preview everything is fine.
Screenshots attached.
I would appreciate your help.

Is this only when migrating a project, or have you tried deleting and reimporting the problem meshes?

I’ve re-imported all the meshes to the 4.20.3 version.
Basically the new project was created from scratch in 4.20.3 but that didn’t solve the lightmass issues
I also checked my other projects and each has the same problems when opened the 4.20.3 version (black meshes after baking)

To sum up :
Scene created & baked in 4.19 looks fine
The same Scene migrated to 4.21preview & baked looks fine

Scene migrated or created from scratch in 4.20.3 & baked looks wrong

Another important thing to note is that if i bake using the Luoshuang’s GPULightmass, the lighting is correct, even in the 4.20.3 version !

Conclusion is that only the version 4.20.3 have problems with the native lightmass calculations

Do you have any possible solutions for that? or maybe it’s better to stay with the 4.19 until the 4.21 will be official ?