Early yesterday I had a Buy Limit order with CMC on USDCHF at 1.015. At around 0830 it spiked down to 1.0147. At 0915 my order was declared filled. This happy situation was ended at 1030 when the fill was cancelled by CMC - Filled in error' it said. Seemed a bit of a coincidence that the trade was powering North at the time. I was wondering if the trade would have been cancelled if it had gone down not up. Am I being cynical here? Should it have been filled?