I just updated to Premiere 2023 after having stuck with 2021 until they finally turned the transcription servers off and forced me to update. Now, in the updated version, I'm unable to modify audio channels on clips that are already on my timelines:
If I right click a clip in my sequence and select "Audio Channels," I get the blank window above. None of the drop down boxes are clickable, so I have no option to actually modify my channels. This is true on all clips in any sequence I try. It's not an issue with the project because it affects clips in other projects within my current production.
This is a feature-length project - starting over and re-selecting audio channels on source clips is not an option here.
Just want to add also that restarting Premiere, the computer itself, and trashing preferences on startup of Premiere do not resolve the issue. Also, I am able to modify audio channels of source clips in my project tabs, but not in my sequences.