Sounds to me more like either air in the system or the manual over ride valve on the front landing gear is not fully closed.. you can TS both of these your selves instead of fiddling around with dealer...
I re read post and don’t see mention of any signs of visible leak...
A “stickion “ problem as referenced for popping noise is not the same issue as what you are experiencing with LG creeping up and down...
Bleed the system and verify that both manual override valves are closed tightly....
This Lippert PDF might help you.....
https://www.lci1.com/images/support/lipsheet/0183.pdf