Not sure if Primal even uses Nostr events for storing bookmarks. Could be wrong, but when adding a bookmark on Primal, no new event was saved to my write relays.
Discussion
That would be weird, its supposed to be a protocol
Yes, well... Primal often acts more like a platform than just a client on a protocol.
there you go https://github.com/damus-io/damus/issues/1024, so it's damus thing