Cue seems glitchy in Nuendo, and “Phones” has no control in Eucontrol (tablet).
Which strongly implies this is a Steinberg problem.
As with several other things Steinberg is woefully behind the curve on this, doesn’t communicate about it much (if at all), and we wait and wait and wait…
Feel free to bump this: Automation system, VCAs, Eucon - Features Request - Nuendo - Steinberg Forums
At the bottom of my OP I mention adding more Eucon functionality.