I too am seeing this. But only in one of the projects I work on. I'm hoping this gets resolved soon.

This isn't the best but its a viable workaround. I'm using the latest Xcode 12 release (Version 12.5.1 (12E507)) and using Xcode 13 beta 5 command line tools. I hope this helps.

Can confirm this is still an issue on 13.2 Beta. But will work if you set Treat Warnings as Errors = No. Not ideal, but is a solution for now.