I noticed in the help file for [thispoly~] that if it is receiving a signal (e.g. when an [adsr~] in a poly voice is feeding a signal into [thispoly~]) that it is in "busy" mode and will not receive note-off messages.
This seems totally paradoxical to me: if a poly voice is told to start playing, then it can never be told to stop playing. I must be misunderstanding something: how does a poly voice ever release if it can't receive note-off messages?