Came across this thread as I have exactly the same setup (K57 and Harpoon wireless) and issue. My computer runs Windows 10. Thought at first it had something to do with using multiple devices on one dongle but no - problem persists. Mouse works fine upon startup but keyboard input is not recognised unless it's wired or I replug the keyboard dongle. Both dongles are plugged directly into the laptop - so not even the docking station.
I have also noticed that the DPI setting of the mouse resets after startup which is slightly annoying.
My suspicion is that iCue is causing the problems.
