IB Options Quotes frequently glitches. I have 2 TWS Optiontrader open both with the same spread. One is frozen, does not update at all while the other works fine. I've lost money before from this glitch so I always double check with 2 accounts open now. There is also a glitch where the quotes for the strike that you have a position in refuses to work, showing blank while the rest of the chain works fine. This is more infrequent. Don't get me started on rejected spread orders..