SHP9500 channel imbalance

The right driver slowly gets quieter until the channel imbalance gets super obvious and then it completely shuts off. Maybe it has to do with the 3.5mm connector as when you move it a bit or you plug it in it affects the imbalance. I tried this with multiple cables, they're not the issue.

Sometimes when I plug in the headphones the right driver doesnt work at all. I've found a few (temporary) fixes: plug the cable in and out until it works, jiggle the cable a bit or shake the headphones. Have you any idea what the issue may be?