This is from the other respitory, its the same premise just on 1.19.2 and I'd like it if it gets fixed.

"From what I could test, using CIT Resewn, the chestplate texture becomes completely dependent on what your worn helmet's CIT resolves to.

Examples:

Using a default helmet will show the default chestplate.
Wearing a named helmet with a full texture will draw that texture to both the helmet and chest slots.
If your helmet CIT texture lacks pixels in the expected chestplate area, it'll effectively break the mod and show nothing.
Hopefully this helps!"

Any update on this?
CIT for 1.20.4 is released and custom textures still seem to be not working

Well CIT resewn doesn't have an official 1.20.4 version, so I guess this is on hold until then