Tearing in sequencer viewport

Hi everyone, I could really use the brains of more experienced users…

I’m


doing some animation tests with Iclone and UDraper, pretty basic things. Using 5.3 and a 3090RTX

When I scrub through the animation in sequencer, i get character tearing, like her head will smear right across the screen and behave horribly.

I’ve also done a quick test in 5.2 with the same animations and I don’t get the same nasties.

All the frame rates are correct, ray tracing is on. I’ve done tests with and without the uDraper plugin and the results don’t change.

Any idea what could cause this in 5.3?