More then likely there is a wiring issue where you are getting something to touch ground and causing the solenoid to release the lid.
I would suggest removing the relay for this trunk lid and then you would need to use your key to access the trunk but if this stops then you know it is either the relay, the switch, or a wiring issue. Otherwise, you would need to be testing the circuit when this happens in order to figure it out. This is why the dealership told you they did not know. It is nearly impossible to catch this in the act so you will need to disable things in order to figure it out. Then when it doesn't act up, you know that was part of the issue.
Removing the relay will remove the power and confirm your issue is inside this circuit.
Let me know if you have questions. Thanks
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Thursday, July 2nd, 2020 AT 4:40 PM