Premiere Pro CC 2017 voice-over recording--no playback sound left headphone speaker

Software Premiere Pro 2017 cc

OS: Windows 7

All OS updates current

Context: Adding voice overs to a multi-cam sequence in the editing pane

Problem: Post voice over recording has no sound in left headphone speaker. And there was nothing online specifically addressing this that I could find as of this date.

Notes: Yet both channels would function normally in Preview pane, Windows media player, and Windows

Previous failed-fix strategies:

1. Edit clip in Adobe Audition failed to fix the problem
2. Restart Premiere
3. Reboot OS
4. These have worked in the past so no scoffing
5. Or any of the so-called solutions that seemed "obvious" by futzing around with the PP CC interface

Likely alternative fix:

1. Open video file in Windows Movie Maker and re-save in corresponding file type
2. Open again in Premiere and Premiere quits acting obstinate just because it can
3. In other words, the file suddenly magically works
4. And WMM is free
5. Ironic, huh

Actual-fix strategy

1. Remove voice over clip from timeline
2. Find corresponding file in Project pane
3. Right click file
4. Then click:
5. Modify
6. Audio Channels
7. See drop-down list:
8. Change from mono to stereo
9. Check box "R": Click box next to the R
10. Click: OK
11. Drag now modified file from Project pane
12. The modified files should work in the timeline