Will try in Cubase 8.5, i have not used the scroll since the update a week ago, but probably the same issue.
On a side-note, Loving 8.5, i just cant keep up with all the changes!
I have Cubase 8 and 8.5 installed on my computer. I can say that the CMC-TP dosen’t scroll in the key editor in scroll (SCRL) mode also in these 2 differents versions of Cubase.