When you go into the nether many chunks will be replaced with other chunks. The chunks that are replaced can already have been loaded, and the duplicate chunks contain blocks that the player has placed. So if you were to place ancient debris in one then you load a new duplicate you double your inventory.
MC-184333
Chunks in the nether duplicate themselves.
Resolved
Awaiting Response
0
Did you modify the save files in any way?
If not, what exactly did you do in order to get this issue to occur?