Server Version#: 1.19.3.2764
Player Version#: 1.10.0.1208-daa6b641
When I am playing a song and press the Windows play/pause button on my keyboard or click the control button in Plex with the mouse, it operates normally. When I touch the screen using my finger, it clicks twice with about 100-200 ms in between causing it to return to whichever mode it was in a second ago.
I found two other posts this year reporting the same problem. I would have responded to them, but they have been automatically closed with no resolution.