LUTs stopped working out of nowhere after update.

I recently updated to CC 2018 as I was told it was a more stable version than CC 2017. I opened an older project which I was working on (with already applied LUTs) and I noticed it was taking a very long time to update the preview. I then saw the "thinking" color wheel mouse icon was going. After about half a minute or more, I finally got a red event notice on the bottom-right-hand corner:

A low-level exception occurred int: AE.ADBE Lumetri (GPUVideoFitler::GetFrameDependencies)

(N.B. Where it says "Fitler", it's not my mistake: I'm transcribing it as is. I'm assuming it should say "Filter", right?)

Anyway, after that I try another LUT, and it apparently applies it but no change is visible in the preview window. I try a couple more, and the same happens. And then I try another, and it starts thinking, and thinking, and thinking, and I finally hit CMD+Opt+Esc and see PP is "not responding", si I force quit the program...

It doesn't always happen in this same progression. Sometimes it becomes unresponsive on the first LUT. Sometimes it shows the red event notice a couple of times and then becomes unresponsive. But after I receive the red event notice, I can't really do that much in PP; it's as if most functions stop working properly, and even quitting makes the program unresponsive. Bottom line is that eventually I always have to force quit the program and that I can no longer use LUTs in Premiere Pro!

My boss is having the same issue on his brand new, high-end Windows PC.

P.D. I'm using a:

MacBook Pro (Retina, 15-inch, Mid 2015)

2,2 GHz Intel Core i7 Processor

16 GB 1600 MHz DDR3 Memory

Intel Iris Pro 1536 MB Graphics