Sorry for mistakes 'cause I'm from Russia).

1st bug is coping of inventoey.This bug works if you've been killed in Nether portal.If you've killed you can't respawn and you need to go to the title menu,then you open your world and see,that you're standing next to portal with all of your items,but your's inventory fall from the portal and you have double inventory.

2nd bug is infinity items.For example you need two damaged bows.I'll show this bug on pictures.