Email does do this, if the recipient is in your contacts. #nostr at least on amethyst, usually does not even if they are in your follows.
Discussion
Yeah, this is a stage problem I've never figured out... we are talking about few hundreds elements. When it happens I usually open my followed list to refresh the cached contacts.
/cc nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z