The fix that will come out in an update should prevent the double entry and empty in model issue from happening. But, for now you can do something to solve the problem after it has happened.
In Finder, Go menu, Go to Folder… paste in this path:
~/Library/Colors/
In that folder, delete any .clr files. You’re likely to recognize some of the names!
Reopen SketchUp and see if your language is the only in model entry, and that it has materials in it.