Wanted to report that I contacted Moog and they helped me a lot. It took a few days between communications but they always got back to me. I made a video explaining the problem, and they asked the following:
And it was! When I switched to the other one it worked they way I expected/wanted! I think it's Mode 1 that I like - I was able to play a staccato note with long sustain of both filter & amp, and then turn down the decay to get notes to end if I need to, whereas in the other setting I wasn't able to.In the Editor, there is a Global Setting for "ENV RELEASE MODE" that sets the behavior of the Release, either being linked to the Decay or Independently controlled. Could you tell em what you have this set to? I'm thinking this setting might be part of why it's behaving that way.
So, the answer was - USER ERROR! And Moog support helped me figure it out!
Also significant - I tried contacting them with the chat feature on the website - no one answered, but I did get an automated email acknowledging my attempt and later on an email from a real person that ended with what seems to be the solution - I've been able to play with my Sirin working properly at least twice since then. So don't give up!