For anyone interested, on March 4th 2022 Elektron User Care has replied to a support ticket regarding NRPN control of Delay parameters
Thanks for the report! I can reproduce this and have now reported the issue to our developers. They will investigate and fix the issue for a future OS. Please let me know if you have any questions.
And asking if NRPN control of Delay parameters is functioning in prior OS versions
I tested with a few prior OS versions and couldn’t find one where this is functioning, unfortunately. I went all the way back to OS 1.10, and I wouldn’t recommend downgrading to an earlier version than that.