Custom Shaders Patch and odd coloured flashing

[ProximateTen]

I just fired up AC tonight for the first time in about a week, and for some odd reason I now get colours flashing on the screen (whole screen). I've narrowed it down to something to do with the throttle/brake, as it appears when I am in high revs and ease of the throttle, depress the brake, or accelerate hard (but mostly it happens when decelerating). I've not changed any settings since I last played it, and disabling the CSP gets rid of the visual artifact. Has anyone else encountered this? I'm running a Radeon RX480 with 8G RAM and a Logitech G29 setup. Any help would be greatly appreciated as going back to vanilla AC is... difficult!

 

[ProximateTen]

Ok I've nailed it down to the Extra FX extension. If I disable this extension it renders perfectly.