Sitesplat, I was wondering if you still code. And if so, if you might switch over this plugin from Minotar to Crafatar.
The minotar API hasn't been updated since 2015. Where Minotar uses the minecraft username, crafatar uses the MinecraftUUID. There is opensource code available to track the MC UUID by entering a minecraft Username.
I nowadays usually see a wrong avatars on my forum. Hope you have some time to take a look at my suggestion. It would be much appreciated.