That’s an unfortunate side-effect off having already ‘employed’ a fully open AHD envelope
This was discussed during testing - so it’s maybe not considered a bug, but it sure is something that merits thought, perhaps adopting a default ADSR along with the Machine swap - but this isn’t necessarily perfect either - or maybe a machine swap can be accompanied by a ‘silencing’ (a bit like a finished envelope)
I wouldn’t be surprised if this evolves, it can catch you out