They wanted the mouse to have a name like “Microsoft® Wireless Notebook Presenter Mouse 8000” but they accidentally used the wrong encoding and the name was invalid. Because they already made thousands of devices without properly testing them, the “obvious” solution was to patch the Bluetooth stack on every single computer in the world to fix this issue. It’s the only Bluetooth device released in computer history that requires this.
I think I read somewhere that they were one of the top Linux contributors back then because of all the device drivers they supplied.