I wonder if it was an edge case that the Linux driver didn’t account for, like a minor incompatibility between the two devices.
You’ve just reminded me that I had a Bluetooth problem with my laptop a few years ago. My headset would connect and work properly, but wouldn’t be recognised after the laptop had either been to sleep or shut down. I had to go through the bluetooth device folder, something like /dev/bluetooth/, find the folder that corresponded with the headset’s address, and delete the cache folder inside. It would then work until the next sleep / shut down.
I expected problems with the Pi because USB wifi has always seemed to be a bit dodgy, even on Windows, and wifi is apparently still a problem area with Linux. Add to that the Pi’s limited distro, and I thought it was bound to go wrong.