I think I messed up. When I read:

This means that you can not purchase via depositing directly from an account at an exchange or equivalent which often change the sender address repeatedly.

I went to my Poloniex account history and never saw my btc address being changed over the past months, so I assumed it was safe and Poloniex isnt an exchange that changes the btc address from time to time. But now it seems Poloniex use a different address themselves for transactions (seeing that on the blockchain). 1.32 btc down the drain?