StellarCore with RGB chat fix makes none of the letters render

[kasa1226]

StellarCore with RGB chat fix makes none of the letters render.
When disabling the fix, rgb chat works just fine with only issues it has anyway.
latest.log
debug.log
Just StellarCore, Mixinbooter, configanytime and RGB chat on 14.23.5.2859 1.12.2 forge
Same issue with cleanroom (0.3.7 and previous versions)