Disappearing backpacks

[michal212345]

Hello everyone,

I made a custom modpack for my partner's RP server. We've been having issues with disappearing backpacks, and I think I have narrowed the problem down to the FTB Essentials /nick command.

It seems that if a player changes their nickname, crafts a backpack, and then changes their nickname again, the backpack breaks. Strangely, when I try to restore a broken backpack, its contents shows for 5-10 seconds and then disappear....

I'm not confident that's the problem but this issue seems to only happen after the player nicks.

[P3pp3rF1y]

What does disappearing backpacks mean? The actual item disappears from player's inventory? Or its contents disappear? Have you perhaps changed the backpack crafting recipe and does its result include any nbt / component data?
Disappearing contents is usually caused by multiple backpacks with duplicate ids existing in the world and that usually happens when backpack stacks are duplicated in creative or backpack is given in quest with id already included or potentially in custom recipe that would also include the id.

[michal212345]

Thanks for the quick reply. To clarify how we discovered this problem, a player complained their backpack items disappeared. We tried to get the items back with the restore backpack command, and when we did, we saw the items for a few seconds before the backpack cleared again. I will do a bit more investigation, but this issue seems to only happen to users who use the FTB Essentials nick command. We don't have any quests that give backpacks. We do have the LootR mod; could this issue be happening because players loot a LootR chest that gives them a backpack with the same ID? Thank you!

[gumballdragon]

Im having the same problem after a server migration, everything transferred over successfully. Logged into the server and saw the contents until the server restarted then the contents disappeared but the backpacks still existed on our backs.