It appears that Deliver on Resolve 16.1 cannot do BOTH of the following:
Export a clip with "export alpha" enabled,andExport only part of the clip (ie, set in and out points).
I've read thread "Exporting videos with an Alpha Background"
https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=63592but it does not address this particular problem.
So: to enable Alpha you have to have Render set to
"Individual clip" ... but then "select in and out points" on Render's timeline are switched off!
Can someone from Blackmagic team confirm this is impossible, and what's the reason?