Hello,

I'd say this is normal depending on the setting of the envelope and on
the setting of the MIDI-interfaces retrigger parameter. All analogue
envelopes without full reset (in fact all the ones that you are using)
ill add up a bit if the time settings are not zero. Before the times of
velocity keyboards good keyboard players used this behaviour to simulate
some velocity like effects.

Set the Attack, Decay and Release values of your envelopes to zero (at
the A-140 set the time range to short) and the sustain to maximum. Then
this behaviour should disappear.

Florian