I cannot find it in the Bolt manual, but I recall reading somewhere that regen will cancel if loss of traction is detected. I don't 100% recall, but I think I did experience this when using the regen paddle on my old 2017 Chevy Volt over potholed roads. Not sure if this carries over to the Bolt but I think the rationale was if regen detects a difference in regen from a drive wheel, the braking assumes something is off about regen and aborts using it until traction comes back.
Regardless if you're in D or L, just pay attention to your speed and go easy on acceleration and deceleration. If you're don't feel proficient enough in L, stick to D. If you're now one with one-pedal driving, I don't see any difference in safety when driving in snow: your leg/foot should already know to translate your "slow driving" thoughts into appropriate "do not lift off pedal in L abruptly cause you'll slow HARD" actions.
2017 Summit White Bolt LT, VIN #83351, built 8/2017 (real range anxiety now).
2017 Kinetic Blue Volt LT, VIN #11925, built 6/2016. (loved it, only fake range anxiety, but traded due to annoying misfires)