US-based banks will often times pass their order books on to banks in Australia or New Zealand just before 5pm NY time. Remember that liquidity drops sharply after 5pm for at least 2 hours until Tokyo gets started and so stop-loss orders are much more vulnerable. The Australasian traders have a quick look at the orders, see if there’s any stops close by, and then get about triggering them.

That’s been their place in life since I’ve been in the FX market. Every European or US trader will have a story about the order fills they’ve received during the Twilight Zone; from the bad to the downright dodgy.