Could be the decimal point/ comma bug playing up.
See this thread:
I have also attached the transforms and constants used in the LG LUT in a txt file.
May be of some help.
LG-Cine Log_to_Rec709 2.4gamma.txt (2.4 KB)
Keep in mind that its for a gamma of 2.4
Another thing to note, 3D LUTS have a 17X17X17, 33X33X33 or (I think) 65X65X65 matrix.
Don’t know if shotcut/ffmpeg supports them all.