SketchUp model faces removed when file->save (validity check)

leg test1.skp (53.6 KB) Hello SketchUp forum members,
I am modeling a leg for a base of a desk.
The leg component was created using two other cutter components, one each for outside and inside profiles. I copied and scaled all 3 components up 1000x, used trim and keep extension, then erased the copies.

When I saved the file I saw two two sections of face removed and can now see inside the model. If I than open the component and add lines to those two faces it repairs them. As I looked back at undo it indicates “validity check” for the file->save operation. Actually even if I close the file without file->save and reopen it, these faces appear removed again.

I also ran cleanup3 and solid inspector2 on the leg block component and they gave no complaints. Why does the SketchUp validty check complain when these extensions dont?
Is there a way to manually invoke validity check other then file->save ?
Suggestion on ways to prevent this in the future. ?

See attached file. At this point the faces have already been deleted in either saving or reopening the file.
Thanks for help.

This could be the problem…

There is a section of 'vertical ’ line that is not on axes.

Or is it meant to be that way…?

Edit:
I repaired the face and I’m not getting and validity issues

Not sure I see which vertical line you are referring to.
How do you invoke the colored axis lines ?

Screenshot 2021-04-03 170010

Thanks. Got it. Forgot where that was located.
The outside vertical face (closest when viewing) is not on axis on purpose. Thats part of the leg shape. The leg inside vertical face is on axis. Tracing over that line will repair the face. If you orbit to the outside, you will see the second face missing. Adding a horizontal line to that will repair it also.
As you noted, these can be repaired. Just wondering why these happen in the first place.

Be aware that color by axis has a tolerance built in. It may color an edge that is actually slightly off axis! It’s a decent quick check, but pretty useless for tracking down minute errors. Setting max precision and either probing with the tape measure or attaching leader texts to vertices is a more reliable method.