Nature of the protocol and how relays work. Not every client is going to pull information from the same relays and it seems, from my experience, that they also constantly recalculate and don’t cache/save earlier data. I regularly come back to a post that I already liked and had already gotten a bunch of likes and zaps, and I see it again with barely a few of its previous stats. I have to go to the post and refresh to get it to update and sync all the secondary data around the post again.