Update from today. Rode quite decent MTB trails today. Sometimes on 50% sometimes on 360%. No issues.
Seems like the problem was dust accumulating around battery connection.
Yeah, I have mine for 7 months now and never had such issues. Did hard enduro on it and commuting as well. The problem started yesterday. I cleaned up everything and it's starting fine. I'll go for "tough" ride today and see how it goes.
I started having the same issue today. It looked like an overheating issue but I was riding for 10 minutes maybe and it wasn't even steep. Everything was cold to the touch.