Just found out I have the same issue with my hi8 pro that I had not tested as a music player yet in the 3 weeks or so since I’ve had it.
The fiddling around with the jack to get full stereo sound is not an acceptable solution. This is a serious design flaw/manufacturing fault, or extremely bad quality control.
Besides bad battery life, sleep of death, awful cameras, awful speaker, this leaves me to wonder if I should ship back the tablet.
buyer beware.