I had same problem with my Lenovo Y70. Removed bottom cover and unplug the monitor connector from the hub and reconnected it. It is located right hand side on the top. That made it better but not fixed.So I also disconnected then reconnected the monitor connector behind the LCD display. This fixed it to 100%. No more blinking/flashing. Im guessing the issue lies in a bad design with the connector on both end for the monitor, they can work there self loose.