Thanks for getting back with the update. One additional quick question for you, when the receiver was connected to the dock, was it located in one of the top-most USB 2.0 ports on the back of the unit?
I ask because it may be that in either scenario you mention that there may be some wireless interference happening in the 2.4Ghz band that the Logitech receiver uses, and we have found that using the receiver in that location on the dock can help.
This type of interference can happen any time a USB 3.0 device is connected to a system (not just our products) and Intel even has a detailed whitepaper on the issue if you are curious -> http://www.intel.com/content/www/us/e…
That you mention the problem can remain even when the dock is disconnected and the receiver is directly attached is most unusual. If placing the receiver in aforementioned location on the dock does not help, can you connect the dock to a USB 3.0 port on one side of your ThinkPad and the USB receiver to a USB 3.0 port on the opposite side of the laptop to see if changes the behavior? Separating them in this manner may help if interference is in fact the cause.
Thank you for your patience!