I’ve got this problem as well on my A2. There is certainly something wrong with the connection port. Mine will connect and start up if I fiddle around with the connection. The challenge is on really janky fast trails, it will fiddle itself lose and disconnect. When I charge it, I have to fiddle the connection as well to get it to connect. Something is definitely wrong with the port on the battery.
I’ll be taking it in to the shop next week and will update if I learn anything.
Love this bike to pieces, but this is super annoying on a $10k Cdn bike…