Dan, I tried resetting the microphone using the command you listed but it did not resolve the problem nor did a prompt a dialog box when I opened Pd. 

On Nov 1, 2020, at 10:26 AM, pd-list-request@lists.iem.at wrote:

You can also reset Microphone permissions system-wide, then (re)start Pd. In Terminal run:

   tccutil reset Microphone

That should trigger the dialog, although it will also reappear for other programs as well.