Every time a player joins, they get another Backpack item.
I have already tried deleting the config folder.
No other plugins except minepacks and luckperms.
Running purpur-1857.

What have you set as ItemName in your config file?

It is default, I deleted the config folder as well.

I must mention, this problem did not occur previously. Only until updating to the latest Purpur builds is this occurring.