Gasoline engines struggle to produce torque at very low RPM's, so once they begin choking on the fibers in the chaps, they lose momentum and stop.

Electric motors on the other hand produce peak torque at 0 RPM, so it's way harder to bring them to a standstill.

Many of these electric chainsaws are premium brands and still have this problem- to my knowledge there are no electric chainsaws that have a safety feature designed to make sure chaps work.

The clever safety feature that could be engineered to help make these safer is to add a torque sensor to the motor that cuts off power if excessive torque is sensed. This excessive torque condition would hopefully be calibrated to not have any nuisance shutoffs, but can still stop the saw when needed for safety.