I did once during the BTC/BCH split. I was shorting ETH and away for a week and all the loans left Polo so instead of closing my positions like they should have they changed my rate to 100X what it was and that liquidated me.
The fuckers.
I wonder if Circle knew just how much resentment Polo created among its users in 2017? They were minting a million a day and yet the place was run like a one-man operation out of Tristan's garage.