Entering a minecart creates duplicate exchange data

Right-clicking to enter a minecart creates a duplicate entry of the last ItemExchange chest you interacted with, but at the location of the minecart when it was clicked.

Reproduce the issue by interacting with an ItemExchange chest, then right-clicking to enter a minecart. Trace the handling for minecart entry and the creation or storage of exchange data. Done means entering a minecart no longer creates a duplicate entry at the minecart's location, while normal exchange behavior remains unchanged.

Written by the indexing model from the issue text.