Skull Seeker Voyage

@lord-eisbox I've seen in chat of some streamers where people are saying they have had this same exact problem and I believe a few streamers have as well so I'm pretty sure it's a bug. Seems I find them easiest through the riddles dropped by Emergent Skeleton Captains so you may try that for now, though you dont find them everytime. You can sometimes get them from loot dropped by Skeleton Ships as well.