Screw stalling during recovery

I have an issue with the screw stalling during recovery. I am testing a mold using Tritan MX731. I have adjusted the barrel heats from the low to high end with no improvement. If I switch back to PP or PS the problem goes away.

Any thoughts on this?

Unlike PP and PS we recommend 60 rpm or less when running Tritan. Higher screw speeds may cause the stall you are seeing.