With b2 on Windows 10 x64, NVIDIA 1080 Ti (391.35), 8700K.
1. LUT thumbnails are incorrect. See screenshot below of the IWLTBAP gels pack. A different LUT seems to be applied to the thumbnail. LUT preview by mousing over the thumbnail is correct. So by mousing over the orange thumbnail with the blue label, the preview window shows the blue LUT you'd expect. It's just the thumbnail that's wrong. Resetting the thumbnail has no effect.

- lut-thumbnails.PNG (67.99 KiB) Viewed 407 times
2. Not a bug as such, but a UX niggle: when a compound node is selected, mousing over a LUT thumbnail scrubs the video but doesn't show the LUT being applied. I suppose this is because you can't apply a LUT to a compound node. In that case, maybe some text overlaid on the video stating as much could save some user confusion?