I tried dyeing my iron armor set black, and then grey. Both sets end up looking like the screenshot below. I'm am running a personal modpack on Forge 11.15.1.1808. I am also running OptiFine 1.8.9 HD U H3. My skin is the Steve format, not the Alex format.

did you solve the problem because i have the same

This is not an issue anymore in the 1.9.4 version and i don't update older versions of Random Things, sorry.