sustain/sampler envelop bug

firstly i've really been enjoying the new 2.3 features - excellent stuff so far! i'm a huge user of the sustain pedal+attack for nice swells and noticed that when i have the pedal pressed, neither the volume envelop or the filter envelop attack works as if it's just turned to 0(the release seems to work still). if i press several keys and hold them minus the sustain pedal, the attacks works/sounds just fine. if i press keys and, mid attack, press the sustain pedal the attack jumps abruptly to an 'off' state.

i've reproduced this bug using several factory sampler presets with my behringer u-control(using an attached sustain pedal and also using the controller's native cc64 on/off button). also i double checked to make sure the volume/filter attacks weren't midi mapped to cc64 and they're not.

let me know if i'm just doing something wrong or, if it is a bug if you need more info...
thanks!