So, I'm not entirely sure how I did it, but I managed to find some weird way of duping items on 1.1.1.6 using other items for the amount, I can't find any posts regarding it and I can't reproduce it.
Managed to do it while splitting a stack of charons for SGS credits with Quinton, was splitting a single charon out of my stack when the value stopped updating, I clicked on it to type when it suddenly exited and I noticed the stack of shirts I now had, I thought it had replaced the charons, but when I left the shop I got the charons back and kept the shirts. The shirts were right where I clicked as well, still trying to reproduce it.