Kontakt and Mach V (like most AU instruments) can play both (what I'm going to call) "tempo-sensitive" and "non-tempo-sensitive" instruments. An example of a "non-tempo-sensitive" instrument might ...
I've also tried this with Kontakt as a VST instrument within Finale . . . with the same results. Some further research indicates that Finale may not be able to transmit host tempo information to a...