I agree it's the drag effect, or lack of it on BL motors.
Some BL motors have more drag on their rotors (magnetically), which makes them harder to turn by hand. If you use one of these then when you are off power that same effect is a bit like drag brake.
Could also be the bodyshell giving you 'push'
Xray T4'16, T4'14 (Wet Car)
Xray X12 2016
wlrc.co.uk (West London Racing Centre)