Weird source code problem of a specific file

After upgrading to Xcode 15.1 on Sonoma, I get a very weird problem in an on-going project.

This source file has no syntax coloring. No matter how I try "Open As->Source Code" it just won't work. All other files (sources/resources) work fine.

Is this a known bug? Is there any way to get syntax coloring back?

Yeah, I solved it myself.

I removed this file from project and re-added it back. Now it works fine.

Weird source code problem of a specific file
 
 
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