Basically the thread title says it all. I just bought a new gaming mouse (Roccat Kova+ if that matters), which is wired and connected to a USB port. I'm still using my same old wireless HP keyboard, which is connected to a different USB port. I'd find it weird that these two have anything at all to do with each other, but all i know is that ever since i plugged in the gaming mouse, my keyboard is sometimes laggy or unresponsive during gameplay (haven't encountered the issue while browsing the internet or any other activity so far).
Improperly shielded cabling with some USB 3.0 devices can interfere with the Bluetooth signal, and it's not as uncommon as you'd initially think. Really all you can do is keep them as far from the Bluetooth adapter as possible or look at getting a wired keyboard. Not a whole lot you can do about it.