console keeps banning friend for "found you duping"

[BagelBoi100]

literally every time my friend joins and he interacts with anything he gets instabanned by the server for "Reason: found you duping" like bro wtf is the console smoking

edit: it happens while opening a cartography table while holding a paper

edit 2: happens with any block you interact with and open an inventory

Edited March 9 by BagelBoi100
update