[5:40 PM] ⚕⚚☤Yes☤⚚⚕: The gem for Mission VIII is only clickable once. Aka if you click it before you get the quest, you can click it when youre on the quest.
[5:41 PM] ⚕⚚☤Yes☤⚚⚕: This is propably server-side, which means that only one person on the server can click it per restart
Excerpt from Discord chat.