The battery BMS - must have over and under charge protection.
A proper Li reg in general will ramp up slowly to max voltage and then actually back off a bit.
And needs to be a series type really - or the stator will be burned out faster as most Li batteries will recharge fast.
The Li reg I have on the Guzzi ramps up slowly for the first 30mins than after an hour at full blast drops a bit. I changed to a modern stator as well - clearly.
I don't know if the KTM has a SHUNT or SERIES reg. I know the big Triumph is a shunt type. Usually are as they're WAY cheaper.