Some Texture packs use Colormaps for colored blocks (e.g faithful PBR by PapaChef), which causes colored wool/concrete to render without its designated color.

The colorMap format seems to be stored as a file located in [base_dir]/minecraft/optifine/colormap/blocks/[block_name].properties

format=fixed
color=[Hex_code]

i don't know how ColorMaps work in-depth, but a reasonable assumption is that OF tints the final texture to color=[Hex_code].

Using OptiFine

Using Iris

The Colormatic mod should handle this.

The Colormatic mod should handle this.

It supports versions up to 1.19.2 only, 1.19.3+ not working.

Anyways, I've made a little script that removes all the colormaps and recolors blocks itself. Works fine with PapaChef's Faithful PBR
It is avaiable here: https://github.com/mrzenc/cmfixer