Quote from loufah:
Is this a relatively recent rule? Around 8 years ago, I was trading slow-moving options a couple times at TD Ameritrade, and I could see my order appear on level II, locking or crossing the market yet not getting filled. TDA didn't think this was out of the ordinary. They said they sent each options order to a specific predetermined venue, regardless of whether it happened to have the best price.
AFAIK it is not a recent rule. if you ever get traded through and you don't get filled IMMEDIATELY call you broker and tell them. this happened to me once and the broker said "you're out at x price - i'm telling you it's confirmed you received this price" even though it wasn't showing up on my platform yet. and when they say that over a recorded line they are legally required to pay you that price.