I'm experiencing a similar issue even though my scenario is a bit different.
I'm using Cubase 10 latest, VEpro 7 latest, Synchron player latest with a yamaha stage piano as a master keyboard but I also tried to use a m32 native instrument keyboard to verify it wasn't just a piano problem. I'm on a windows 10 pc with my old rme fireface 800.
When I play, usually, the octaves where I trigger the notes play with no issues while the octaves with key switches on or not assigned (the greyed keys) are not triggered (I play on the keyboard in the right octave but no animation is shown or articulation selected) . If I move around the keyboard sometimes I can trigger those keys but at different octaves (let's say I have key switches on C1-F1 but I have to use randomly C3-F3 or C2-F2 or even C7-F7 to trigger them). As I said I have the same behaviour using the yamaha piano and/or NI m32 master. If you need it I can email you my cubase-vep template in order to find out if its a reproducible problem or something specific to my system.
Thanks
Walt!