We had a brief discussion about this and none of us can remember this working differently. Basically, when you’re in monosynth (when poly is turned off), it basically acts like a monosynth where your first velocity input is your velocity and doesn’t change until the voice is totally dead.
There could be improvements made to this functionality, maybe something like when Retrigger is on, the behavior updates the velocity levels or maybe it interpolates to the new velocity over the attack time or something.
It’s more a synth than a midi instrument, for sure.
For the time being, it’s probably just good to take note of this behavior, I’m not sure when we’ll have a chance to tackle this–that is, I’m not convinced it’s necessarily a bug.