I have a 2021 (just one week) and no 2018 experience to compare it to.
That said, when trying he one-pedal mode I never had to hit the brake.
As one other poster implies: It it my understanding that if by chance what's going on was you'd just pulled out of the driveway with the Bolt at or darn close to 100% charged it won't do any or much regen braking. That's to keep from overcharging the battery.