2007 Chevy Tahoe LTZ rear door opens 30 % and returns to closed position when I use the push button on gate. If i ust the phob it does same thing. If i us the switch insine side issue.

 

I don't think these have the ability to 'learn' height options.... so, at 10 years old, I'm guessing that your lift shocks are shot. Try to manually open/close the hatch. If it's super heavy, the motor can't lift it and gives up... (also a safety issue).

Replace the gas struts and try again.