Hang on… upon further testing, if none of the V and A rows are selected on their row header at the left, you can drag video only and drag audio only with no problem.
If ONLY the V1 row is selected, can’t drag audio only. If ONLY the A1 row is selected, can’t drag video only.
There must be a reason for it working this way, but to those of us that haven’t had formal training for Premiere Pro… double ugh! lol