Here: http://rationalqm.us/hdr/avscube_1.1.rar
Again, Doom9 is the international encoding portal for broadcast engineers, encoders and linear algebra lovers as well as normal users. Whether you are using Avisynth, Avisynth+, AVXSynth, VapourSynth, ffmpeg or other legacy programmes like VirtualDub, Gordian Knot etc, Doom9 is a major reference point. I use to write there quite a lot and there are very skilled developers.
For instance, although I made the LUTs, nothing would have been possible without videoh who ported the plugin "Cube" from VapourSynth: https://forum.doom9.org/showthread.php?t=175552&page=3
There are many users on Doom9 asking many different questions and you'll probably find answers about any possible video artifact you can find and how to deal with it with your favorite frameserver.
I wouldn't be surprised if Steinar has an account on Doom9 as well.
Cheers,
Frank.