I managed to do a recording, The quality isn't all that crash hot but you can see the problem. Also the flickering only happens in a window, when I switched to full screen via ALT-ENTER the flickering went away. The other only problem maybe would be to try to increase the frame rate. I don't how how you initilize the plugin but maybe a PROC LATE or shadow_stencil=4 "Or is this done via initilization in our scripts. Overall I reckon it's a great contrib.

Here is the link to the flicker problem Flicker Problem