First, to those who don't see the problem here, the OP put a limit in inside the current spread and it doesn't show up for the rest of the world to see. Some securities, SPX option spreads are a great example, show a fairly wide bid/ask spread, but you're almost always hit if you bid/offer 5 cents (minimum tick) off the mid...Except if you're seeing this IB behavior and they don't send your order to the market. Then no-one knows you're willing to offer just above/below the mid so they can't and don't fill your order. This is absolutely unacceptable, and its baffling why IB thinks its OK, except that they just don't seem to care.
To the OP, this is standard IB behavior. They claim that they've determined your order isn't marketable (which is utter BS if you're inside the spread, but they do it anyway) so they're "holding" it until it is. It actually gets worse, you can have a futures position on in something illiquid like an out month corn contract and they won't even submit a market order to the market when you enter it because they somehow decided the market isn't trading at a reasonable level. This should be illegal, but somehow that concept of FINRA policing its own just doesn't seem to lead to any action, crazy I know. However it does take just a few minutes to submit a report online with FINRA, so please do. For what its worth, you can sometimes get around this behavior by specifying the exchange instead of using SMART order routing.