Logitech G15/G19 keyboards are notorious for this. Later revisions and refurbs correct this USB connection issue.
Logitech's LGS software sometimes starts up after an odd delay, long after the WinOS boot process, and sometimes "loses" the keyboard during driver initialization and USB (re)enumeration.
Technically, USB1.x/2.x connector specs actually specify a fifth "pin" - the metal connector shell itself - to serve as an electrical ground. Not strictly necessary (as Pin 4 is already USB Ground), just a failsafe redundancy for maximum current handling to ensure signal reliability. Many (most?) USB1.x/2.x device manufacturers basically ignore this "pin 5" connector, it has a weak electrical connection and isn't actually soldered into place on their devices/cables. Logitech sometimes used such cheap (non-compliant) USB cables in their peripherals.
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