During 1.19 using the light on pedal modifier (crtl + s) or even regular breaking did not lock your wheels meaning you could maintain the turning control over your vehicle while breaking.
On the 1.20 if you use light break, the momentum compared to heavy on pedal breaking is slower but after a moment the brake will still apply to maximum causing wheels to lock and being unable to maintain control while breaking.
In short before it seems that the light on pedal brake limited the brake not to hit 100% on last version, but now instead it slows it down the acceleration of breaking lightly but still applying the brake to 100%.