Compressor Add surround group incredibly slow

After tagging the various audio files for this option, the beach ball appears and spins for several minutes. After that applying a preset spins the ball for another few minutes. Eventually it settles in and allows the job to be submitted. Compressor 4.9 on an 2019 MacPro. Although it has been happening this way since 2019.

Alternatively, running compressor 3.5 on an old cheese grater not only lets me drag and drop the audio files on the various channels of the surround group, there is not delay in the process. All in, it's just a tad slower to complete the process than the 2019 MacPro.

All other compressor tasks run just fine, with no speed delays.

What am I doing wrong?