Caustic Song file (optional):
The decay envelope sometimes resets (fully closes) when the first note trigger of a sequence stops. Subsequent note triggers do not have this behaviour.
To expand on that, I've attached a caustic file. Have a listen. You might be able to hear the filter sweep closing extra hard on the first chord out of every 4, since it's on a simple 4 trigger loop.
Have a look at the oscilliscope showing the envelope output, and notice that when the first note is no longer being triggered, the decay envelope goes immediately to zero - but it does NOT do that for the other three notes.
I believe this is a bug, and it should never close the decay envelope automatically, no matter what notes are playing or not.
While saving my file to attach, it fixed itself. but only partially! Sometimes I can get it to still happen, especially just after adjusting the size of the note. It's quite audible when it does happen.
Oh well, there's certainly a bug here, but it appears reproducing it is not quite as straightforward as I thought. Here's the file anyway, maybe it happens for you, maybe not. I had much more luck reproducing it on android than on windows...
Maybe something to do with processor time available?