When trying to buy a really small amount of BTC, it gives the error message "1: Amount too low". I suspect the '1:' is some sort of error code? Perhaps it's more useful to mention the minimal amount in the error message.
EDIT: Found a more serious one now.
I set a buy order at a ridiculously large amount of a million BTC for market price, at 1:250 leverage. I had $14k in my balance. Then something weird happened: the order got executed for 250.82679898 BTC (worth exactly $25k), but my balance remained untouched. Then the order was canceled automatically (and it is now listed as 'canceled' in my 'Closed orders' list) because the 'Margin allowance exceeded'. Not everything was unchanged, though: my fee-progress-bar jumped straight through four levels, to the point where it's now nearly at 0.36%. Being able to use this in a controlled fashion would make it a very viable attack to get into cheaper fee regions
I have thus been unable to reproduce it, but I'll keep trying. Perhaps you can see more info on the back end. It's trade order OYHWZH-PXEQY-PWFHKU.
EDIT: Found a more serious one now.
I set a buy order at a ridiculously large amount of a million BTC for market price, at 1:250 leverage. I had $14k in my balance. Then something weird happened: the order got executed for 250.82679898 BTC (worth exactly $25k), but my balance remained untouched. Then the order was canceled automatically (and it is now listed as 'canceled' in my 'Closed orders' list) because the 'Margin allowance exceeded'. Not everything was unchanged, though: my fee-progress-bar jumped straight through four levels, to the point where it's now nearly at 0.36%. Being able to use this in a controlled fashion would make it a very viable attack to get into cheaper fee regions
I have thus been unable to reproduce it, but I'll keep trying. Perhaps you can see more info on the back end. It's trade order OYHWZH-PXEQY-PWFHKU.