You may have got lucky. You may have got a cancelled order car and you so happened to order the exact same spec/one that could be slightly altered as it was very early in build process
I'd recommend you speak to Audi to get a diagnostic check to see if any fault codes flag up. If it's not an issue with the car then it's an issue with the charger.
Could it be an issue with the comfort control module which should be situated on the passenger side floor under the carpet. Especially if carpet has gotten wet.
Welcome to the forum you'll find the members on here are a friendly and helpful bunch 🙂 look forward to seeing some pics to help identify it but I'm sure it's a b7.
Does sound more mechanical than electrical but you could get as diagnostic check to see if any fault codes flag up. When was the gearbox last serviced?
If it's the torque converter or clutch I'd get this sorted asap.