Hmmm... Like I said in the beginning, my understanding can certainly be wrong!

FXCM's web site is quite the labyrinth, and I haven't seen where the trading times of different products is shown. On other websites, however, they say US30, NAS100, & others are traded in Chicago and trading ends daily at 4:15. Therefore, I assumed that FXCM would follow suit. Or even if FXCM still trades these, volume drops to nothing because the underlying market is closed. And therefore is isn't a simple, transient, momentary illiquidity - it's either exactly or almost exactly market closed. And therefore something to be accounted for.

But if all that's wrong and it's simple, transient, momentary illiquidity, then I stand corrected. It does seem, however, that twice in 48 hours at exactly the same time of day is pretty far out on the probability curve...

Thanks.