I had the same issue, but solved it. I did a search on my C drive for all Kontakt 5.dll files. I could tell by “date modified” which ones were the most recent. I removed all old .dll files from the cubase vst plugin folder, and copied over the newer ones. Basically, Kontakt inside Cubase is looking at the old dll files still and by locating, copying and pasting the newer ones into the right folder solves the problem.