Clover just killed itself?

So, weirdest thing:

I was planning on doing a fresh system installation this evening but hadn't started preparing yet. Went out to get some groceries while my High Sierra system was running and came back to a "insert proper boot device and press any key" message on my screen.

Restarted the computer and apparently Windows UEFI boot manager has taken over control and Clover is nowhere to be found.

I've been trying to reinstall the system now and I'm getting kernel panics all over the place while trying to start the High Sierra installer.

Anyone had something like this happen to them before? The system ran rock solid for 6+ months before this.