So in the morning it started up and no problems hours later the missing keys are back. Same ones as before. (In my case C#6 to G#6 Roland numbering)
Note that channel aftertouch still works on those keys, if that helps rectify the problem.
Also using the octave shift switches moves the midi notes but not the keys. The same physical keys don't play no matter what the transpose.
(so at least I can use it as a pseudo 61 note keyboard till this gets fixed!)
(Using Snoize midi monitor software to verify all this.)
Arturia reply please?