I has to do with the legitimate spread on L2. There was a Bid @6 and an Ask @7 When the Bid/Ask was filled, the next Bid was 6 and the next L2 Ask was 14 The next Bid is again 6 and the next Ask is 16 If no one jumps in and puts in a higher Bid than 6 or a lower Ask than 14, it will remain as is forever (or until the MMs get tired of no movement and do a paint job). If the 14 Bid gets filled or retired, the jump will be to 16.
TDAmeritrade pulls all Bid/Ask from their MM’s Book at close of business each day even if the orders are GTC. Scottrade leaves all Bid/Ask on the Book that are GTC. That is one of the reasons why you can see a major Bid/Ask fluctuations at open. The Bids and Asks were there but pending opening bell. I have a standing Sell order for 1 million shares at double the closing bell highest Bid or 150% of the closing bell Ask; whichever is greater.