You mentioned that the Organelle would reset if you bumped the power supply’s tip - this could be an indication that the power jack’s solder connection is loose. This could also explain the grounding issue.
That could be the case. If you have a soldering iron, you could hit up the pads just to make sure.
Maybe the ground pad on the inner surface of the enclosure around one of the holes for a pot shaft needs a light sanding?
It could also be an issue with the power supply’s tip. Do you have another one you can try? The Organelle requires a power supply with the following specs: 9VDC, minimum 1000 milliamps (1.0 Amp), and a 2.1mm barrel tip with center-positive polarity.