This is the 3rd time this has happened to me in as many months with 3 different stocks and i can never get an answer as to why. Placed order with IB to sell a GWK2 Jan 90 call for $2.45 at 10:40 with the spread at $2.35x $2.60, option modeler showing $2.46. 10:44 spread is still 2.35x2.60 only now the model price is below my ask. 10:45 my ask is now displayed. I thought with electronic transfer the exchanges had to post immediately instead of holding the order to see which way the market was moving. This was on Philly but have had the same problem with CBOE.
I don't really know the answer - except that this has been going on for years at Philly. They are slow to update their quotes - at least at IB. And you may see your trade go through - for example I saw a 7 contract order "printed" last sale at my price yet my order was still green. I was pretty sure I was filled but it took several before my order line showed the fill. To add insult to injury I have cancelled what looked like outstanding orders that had been already filled at Philly. IB charges the cancel fee even though the order was filled! There's no excuse for this. Philly keeps on playing games.