It has happened to several people so far. You need run through the dead 12 V battery procedure in owners manual. You open the car with the mechanical emergency key, use an external 12 V jump battery on to post on fuse box to open the front trunk to access the battery and then jump the 12 V battery. The car should then wake up.
They sorted very quickly up and running within the hour
next problem has been the app connecting to PCM its so unstable
any way the car is great I had a Tesla S for 4 years there electronics were amazing never had an issue ,its just the taycan drives better and much better seating and all round looks.
I had the flat legacy "12v" battery problem yesterday. Had to get Porsche Assitance. Now know how to fix it myself. The cause of the flat batetry was because I left it plugged into my 7kw house charger for 3 days. It charged the lithium battery and then drained the "12v" battery.
This is crazy. I am sure Tesla don't have this problem. Porsche are aware of this.