This happens in both Kontakt (latest version) run as standalone and when running it as a plug-in in a DAW.
The "Play Mode" dropdown list shows "nil" and when clicking on it, the following error gets thrown:
SCRIPT WARNING (Line: 1653, Script: 1): Array index out of range (using default value 0)!
It's just the list that seems bugged. Using the arrows instead cycles through the other modes and they work as expected.