Well I started this modpack and i completed the first chapter ok ?Then i invited someone who restarted the island and everything.And he invited me to a party.We both got all the rewards 2x time from the first chapter please remove it mym developers. Proof ? Reproduce the bugs exactly as I say : Step 1 Complete all the quests without these quests ,,Productivity'' ; ,,Wool'' ; ,,Powering'' and ,,Labwareand Samples'' Step 2 Invite a player without any quests done onto your island. Step 3 Tell him to make a party and invite you. Step 4 Join the party and then you find out tons of rewards.
sadly this is how the quest book its suppose to be if someone joins your party or his you guys will get double the reward its not a bug its how the quest book works you can go to party setting and set it from multiple rewards to only 1 player
Your party is set to "Multiple rewards." This is so that you can't join a new user's island with quests already finished, and prevent progress, if you're both starting from the beginning and don't want those two rewards, then he has to change the party rewards settings himself.
Closing as nothing we can do here to fix other then forcing everybody to not be able to share rewards.