“Bluemotion bug”? –> Battery problems

Hello, I had 3 strong battery discharges so far, which I can’t explain. The first time the battery was completely empty after a weekend. That’s 2 months ago. The last two times the car had to fight hard to jump on (the battery sign flashed on it). Only last Saturday it happened again. In the afternoon I drove the car out of the garage to pull the tire screws. When I drove it back into the garage and parked it I went a little too early from the Kup It did not make any jumper but it was noticeable that I went a tick too early from the clutch. In the evening it then came to the mentioned cause problem again. Can it be that at this too early from the clutch go the stop/start automatic was triggered or otherwise any electrical processes that lead to a fast discharge? Or is simply the battery defective? It should be noted that I have the car every day approx. 50km drive. Occasionally there is a day where I do not move the car, but that is very rare. Greeting Michael