It can, but if a new bookmark event from another relay shows up on Citrine, that would erase the older one as well.
Discussion
Fair, but that might be less likely to happen. For the most part, Citrine is only available for local clients to write to, unless you expose it via Orbot to access it over Tor.
Or you receive the empty event on Amethyst and add a new one. Amethyst would then update Citrine.
Interesting. Didn't know Amethyst was forwarding new events seen on your other relays to others that are missing the event. That's handy, but definitely doesn't help with this particular issue. 😂