There does seem to be a TSB on this (which in my experience here, dealers don't look up for whatever reason).
This is for 2019 e-trons
Condition
Customer states:
- The rear lid closes without any input.
- At the time of the concern, the key was in the immediate vicinity of the vehicle’s trunk. Workshop findings:
No applicable DTCs are stored.
Technical Background
Unintentional deployment of the gesture-controlled rear lid because of sensitive triggering.
Production Solution
Updated ZDC in the rear lid control module, J938 (address word 006E).
Service
SVM Update Instructions
1. Follow all instructions in TSB 2011732: 00 Software Version Management (SVM), operating instructions.
2. Update the rear lid control module, J938 (address word 006E) using the SVM action code as listed in the table
below, if necessary: