Bright side of gameobjects becomes much darker after baking

Hello,
I've googled a lot for answers about similar issues, I thought many people would have experienced the same, but still these topics are different or under different environment.

I have this simple scene, and only one directional light set as Mixed, some gameobjects, their bright side (only one, not all bright sides) become much darker after I baked a light map, which is totally not correct.

Please see the screenshot, I put all settings that I think might be related to this.
I'd like to know what I can change on the settings to correct that issue.

Thanks very much.

PS: If Lighting Mode is set to Baked Indirect, it's much better, almost correct. But Shadowmask mode will lead to that issue.

 

@Solidcomer
It's possible that the "normals" on that part of the model, might be facing the wrong direction. You might have to flip or recalculate them to face outward. I had a problem similar to this, and that is what solved it for me.

Also, I wonder if this might be some strange problem, with mixed lighting? Hmmm.

 

It was with baked lighting, and I checked agian, these are very basic Probuilder objects, and I didn't found any clue related to normals, anyway, in a complex environment with only mixed lighting, it's not very obvious, but it's kind of strange anyway.

Thanks very much for your attention and reply.