- Bootcamp into MacOS X.
- Use System Preferences > Bluetooth to unpair the device.
- Bootcamp into Windows
- Use Control Panel (different sub-tool per version) to pair with the device.
- Bootcamp back into MaxOS X.
- Use System Preferences > Bluetooth to pair with the device again.
- It otter work in both environments, now.
Long story: I think that basically, the device is getting confused because it's been paired with "a computer" just fine, and sees no point in re-pairing with the same computer. I could be totally wrong. But that'd mean that the MacOS side of things is just being especially clever, seeing that Windows is already paired, and re-using those connection credentials. Basically, I'll bet the Mac is pretending to be the existing paired Windows sytem .. while Windows has no idea it needs to share. That's my story and I'm sticking to it.
Hopefully this helps someone else. There are a bunch of discussions about this, scattered across the web, that detail the drop-pair-repair method. But half of them are those stupid sites that've scraped someone else's content and plastered it with ads and premium-membership scams. Honestly, I wish there was a Google preference I could set that'd just ignore those bozos every time I search.
I wonder how you'd determine that a site is scraped content with ads and membership offers. If you just used domain name, they'd go and register new domains all the time to dodge the blacklisting. Perhaps some sort of "deprecate sites with more than X ads" heuristic. If anyone's got an idea, I'd love to hear it.