Is that a per-level palette, or a desaturated colourmap (https://wiki.srb2.org/wiki/Linedef_type_606)?
Do you have OpenGL shaders enabled or disabled?
@Zwip-Zwap_Zapony Per level. Just looked into the pk3. or it appears to be looking at the files. Not entirely sure.
Kodachrome uses a special palette, so GL may not be reading from the level-specific palette.
@Zwip-Zwap_Zapony As Yume said before, it is per-level (I think), and answering the second question i have the shaders enabled