Trying to load a resourcepack that changes the color of spawn eggs causes an error and the pack isn't loaded

Resourcepack:
https://drive.google.com/file/d/1v6Wj2w-jUMfxG2iPGo4HoEIZNSS1OujC/view?usp=sharing

The color.properties file:
https://pastebin.com/pT7UM7cb

Log:
https://pastebin.com/FTyPKDXR

This is 1.16 but the issue is also on 1.18, only using 1.16 as the log in this version shows more information.