Could be something to do with the way Primal caches relay events.

Pinging the developers nostr:npub16c0nh3dnadzqpm76uctf5hqhe2lny344zsmpm6feee9p5rdxaa9q586nvr (Primal) and nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z (Amethyst) who will probably give you a better answer than I can.