Quote from tmarket:
I am curious as to how much of a position you have in IB, just a percentage of your portfolio will do. I have no position in IB or any other brokers.
I suggest you try leaving your TWS running overnight (make sure you set the mandatory automatic log off properly so that it will keep running), if you are really interested in reproducing this problem. TWS, if running at around 12AM Eastern, will get disconnected from the TWS server at that time for a few minutes to tens of minutes. TWS will not shut down, but try to reconnect by itself. It will often be successful, apparently, at the reconnection. The problem is, sometimes, the next trades you do in next session will not show up in TWS. You can place an order and it gets filled and there will be no indication of the fill. Sometimes, there will be an audio indication of fill, but no such fill showed up in TWS until you restart TWS.
This is an indication that the TWS server is out of sync with TWS running on your PC.