Sounds like a KVM Switch programmable mode, rather than a bug. It looks like on some packages, the control key is an alternate mode-switching key and a double-tap (a common occurrence) puts you in programmable mode.
I am reminded of the Windows sequence of 5 rapid taps of the shift key putting you in Accessible mode. Many people would inadvertently enable Sticky Keys while playing FPS games.
From a random IOGEAR KVM Switch manual:
By default, all of the following commands begin by pressing the
[Scroll Lock] key twice. A few PC key
- boards and all Apple keyboards do not have a [Scroll Lock] key. If you have one of these keyboards you must use the alternate toggle key
of [Control] instead.
[...]
You may enter advanced hotkey mode by pressing and
holding [Num Lock] on the number pad, then pressing the [-] key on the
number pad and immediately releasing both keys.
[...]
If you have done this correctly the Caps Lock and Scroll Lock
lights on the keyboard should begin flashing. This means you are in
hotkey mode, which will be shortened to just [HKM] below. If you are
having trouble entering hotkey mode press [Esc] and try again.