You brought this up in the matrix room, so I will try to put down here a summary of what I responded in there so that it lives in a more permanent fashion.
Lots of profile changes are not federated out in realtime, extra fields being one of them. Instead, your profile, as seen on remote instances, is only refreshed periodically. In the case of PieFed, when an instance receives an activity from a user (post/vote/comment), and their profile information hasn't been refreshed within the past 24 hours, then the instance will query your home instance to make sure it is up to date.
What this means is that if you update your extra fields right now, it can be up to 24 hours before that has propagated out to remote instances depending on when your profile was last refreshed on their instance. It could be even longer if you don't federate any activities out in that time.
A very similar process also happens for lemmy as well as for other "actors" in the ActivityPub parlance. This includes communities and feeds.