Maybe try to keep an eye out on ebay. Anyone that's upgraded from a vive to a Vive pro with just the headset would theoretically have a vive that's no longer usable, as the lighthouses and controllers are being used with their pro.
I've experienced the same thing on my Vive Pro after an NVIDIA driver update to the most recent. rebooting my PC seemed to fix it, but it's popped up a few times randomly. again, with PC reboots fixing it. I've got friends reporting the same thing post driver update.