There are different "grabby brake" issues, which I believe are all areas that lack programming refinement:
1) Brake Assist
LEAF features Brake Assist, which will increase brake pressure when it detects a panic brake attempt by the driver. This can cause the brakes to grab hard and not let go even when you release the brake. It's designed to bring the car to a complete stop since drivers tend to not apply full pressure on the brakes in an emergency where they should. This is an annoying feature, and it can sometimes activate when you don't mean for it to. Fully releasing the brake and pressing the accelerator will stop Brake Assist.
2) Grabby Brakes
Unusually touchy brakes, usually when you're riding your brake such as in traffic conditions, tends to happen in cooler temperatures. It's probably a glitch in regen programming. Workaround: Fully lift off the brake pedal and then re-apply the brakes always fixes the problem until your next braking event.
3) Pulsing Brakes
Touchy/sensitive for one half a second, normal for another half second- repeats. This pulsing can be corrected the same way a grabby brake can be corrected- fully lift off the brake pedal and reapply the brakes.
Then there's the sort of unrelated "ungrabby brakes". If braking while hitting a sharp bump in the road / pothole, anti-lock braking may kick in, significantly reducing braking pressure in one or more wheels, usually at the worst possible time such as slowing while approaching stopped traffic. All anti-lock brake cars do this to some extent, but LEAFs system is overly aggressive (this becomes incredibly apparent in winter weather conditions when roads are slippery- the car will aggressively anti-lock- to the point of making the car unsafe).
2012 Nissan LEAF SV
20% degradation in 42k miles
Leased 5-17-2012, Returned 1-15-2016
2017 Chevy Volt LT
Siren Red Tintcoat