Could it be because you’re spelling it together as Prismshift rather than Prism Shift? It’s algorithm 9806.

In the algorithm search, if you type “Poly” you’ll see PolySynth (9809), PolyFlex (9805), Polyphony (9802) – the new H90 polyphonic algorithms
In the search, if you type “vocal’ you see VocalTune (9810), VocalShiftMIDI (9804), and VocalShit (9803) – the new H9000 vocal algorithms