Hey!
As subj says: LUT filter doesn’t apply if the lut file is located on the system path, which contains cyrillic characters.
In my example on video I use same *.cube file (black and white profile), but with a different sys paths.
Tested on v21.09.20 and v21.08.29 (both win7 x64).
Thanks!
PS: ‘Відео’ for fast test