Ah yes, I`m very familiar. Last summer(I think) I was trading TASR options and my SMART order got routed to the AMEX. An hour later after I had flipped out for a few points the AMEX busted all option trades in TASR.
The first F`d up part is I covered so instead of being flat and in the green nicely I was short and in the red horribly...the second F`d up part is the AMEX was the only exchange to halt trading in said options. Never gave a reason besides "system problems". My speculation is that some huge MM firm fat fingered multiple orders and was gonna be put out of biz in a matter of seconds so they just did what criminals do...they lied.
I have not traded one single contract on the AMEX since then.