I think, that what you exsperience is, that all the modulators in the center strip give a little modulation if they are'nt set to 0.00 modulation. This can be audioble, unless you do something to avoid that.
That said, then in which real world sound case would you on a pluck sound like this modulate the wavetable volume only, leave the Filter cutoff at maximum, have full sustain on the Amp envelope and hold the note at the same time, even after the pluck sound you wan't have played it's pluck cycle? Especially if you are nor satisfied with the result, and you can do something avout it.
If you in example also let the same envelope modulate the Engine 1 Output volume instead of setting this to +12 db, then you'll get no output ("leak") at all.
There are many things you could modulate to avoid your "leak", and get the result you wan't.
The two easiest ways would be:
1. if you simply did'nt use modulators at all, but just the VCA Amp to shape the pluck
2. or in example just select the ENV2 as modulator for the AMP MOD, unless you have other usage for the AMP MOD.
But yes - as said, then all the modulators in the center strip including the envelopes apparantly give a little modulation just by being "switched" on, so to speak.
I can't tell, if it is chosen by design or an oversigt or bug, that just activating a modulator with a negtive or positive value give a modulation even if the given modulator is at a zero point. Perhaps Arturia will tell. That would be nice. It 's not something one exspect.