Playing around with Catodon and really enjoying it. I just thought it was really interesting to note that emoji reactions do federate. Although for some reason Piefed shows 2 when there's only 1.
For those unfamiliar "'keys" are the many Misskey forks. i.e. Catodon, Iceshrimp, Sharkey, etc.
Both of the reactions are user with one and the same name, Dylan, which is apparently @Dylan@catodon.rocks . So, looks like it's a bug and not something that would have to do with one instance being federated with another while a second instance is not.
To help @wjs018@piefed.wjs018.xyz with debugging, here's a link to the comment in question: https://piefed.social/post/2552116#comment_13537279