I'm running into a strange issue with the Sterling API where it seems it decides to stop sending _ISTIPositionEvents_OnSTIPositionUpdateEventHandler randomly, even though RegisterForPositions() is called on start and DeRegisterForPosition() is not called. I am getting PositionUpdates for a while then they just stop appearing (even when the positions are changing). Quotes are still coming through correctly though. Does anyone have any experience with this problem? Thanks.