Running into this as well. I downloaded the xib from developer site and it fixed it, but then I quit Xcode, reopened it and the error came back! Replacing it with a fresh copy works each time, but definitely looking for a solution to this!

I'm seeing this as well so was wondering if there was something else I had to do to add support for macOS. I only just started testing my app on the desktop, but I'm unable to control it with the media keys under Monterey 12.0.1. Following this thread.

Here's a CPU capture of the different states.