It happens when:
1) charging finishes,
2) you wake up the car, and it tops up (no matter how small), and,
3) if you have scheduled charging set, so the car wakes up to charge, but is already full.
The most likely culprit is you waking up the car with the fob or mobile key. If you turn off passive unlock, does the issue go away? (I know it’s a workaround; it would just help identify if this is a real bug or actually the wake up issue)