So, this is probably less of a bug, and more of a "we never updated it" type situation.

On main, since recently (ish) we've been able to use colour codes as patrons every 10 seconds.
I remember a time when colour code cooldowns were much longer, but this might be my memory betraying me.
I think that the cooldown was never updated on Skyblock, and as such, still remains to be 10 minutes instead of the default 10 seconds.

Since patron is a global feature, i thought i should probably report this as i don't think this is intentional, and it's quite annoying especially since you kind of have to use 1.12.2 to play skyblock, which makes hopping to main for a quick colour-coded trade message, or anything of the sort, basically impossibly difficult.

How to recreate:
Hop on skyblock and try to use colour codes twice within a minute.
@TomKFC tested it in game real quick because he didn't believe me at first, he confirmed it's indeed 10 minutes.