Lens effect disappearing when adjusting on high res renders

[justini]

I've just completed a 12x1 cubic render (24000x2000 pixels) and trying to adjust the lens effect.

2 problems here:

1 )When I adjust any parameter the effect disappears entirely (I get a black glare element).
2) I can reload the image from the history and the effect will return using the settings from when it finished rendering, BUT, even though i've changed the settings, reloading the image doesn't visibly return the settings to what they were when it was rendered.

[justini]

Turning off Hardware Acceleration seems to get it working again briefly but is not reliable and is exceedingly slow and quite unusable. Is this just a limitation of GPU RAM? I am using a GTX 1080 TI.