Wait so you got a new battery? Or you're bike-less while they figure out this problem??
Sounds like he is bikeless while they figure it out.
The things that typically could cause this to happen are.
A. A balancing leg got disconnected somehow and that arm is not balancing properly.
B. The cell(s) had a manufacturers defect in it, and stuff needs to be replaced
C. The battery was old to begin with, and this would be normal wear showing. Much like the zero's have chronic battery problems as they age.
The proper fix, would be to just replace the entire battery with a new one, since this supposedly new bike, supposedly had a new battery in it to begin with, and is only a month or two old. This is so they can get his bike back to him in a timely manner. Then they can disassemble the old battery and do a thorough failure root cause analysis at a later time at their leisure, when it is not disrupting their customer, while his warranty runs out with the bike in the shop!
I have seen Energica do this a few times, just swap it out, or actually send a tech and battery, or whatever, out to the customer to fix it on site if possible. When a company goes to that extent to take care of their customer, it shows they are a Top Tier Corporation.
The short version:
He has a battery problem on a brand new bike.
Fine.. swap it out
Get him back on the road NOW, rather than weeks or months later.
Keep the customer happy.
Figure out WTF happened to the battery so it don't happen again.
It'll be interesting to watch the process. Hopefully they get him taken care of in a timely manner, especially since the weather is heading towards nicer times to be riding !!
Aaron