It appears that any Builder taking a color parameter, if handed, say 0xcc88cc interprets this, not as just RGB, but as if it was given as ARGB as 0x00cc88cc. That is, it interprets a given 24bit RGB color - intended to have no alpha channel - as if it is a color with full transparency when it should see it as 0xffcc88cc.

@friendlyhj since #240 is merged, is this fixed?

Fixed. Although I wonder why build failed.

Build fixed, so I'll close this then
https://www.curseforge.com/minecraft/mc-mods/contenttweaker/files/3383429