Hello,
I regularly use my 3650 as a modem for my laptop and desktop, connecting to it via bluetooth dialup. When the phone is pretty much at its factory settings, this connection works reliably. However, once I start adding to the phone, the connection stability degrades severely.
After several reformats, and some trial and error, the culprit looks to be Opera. Up until I install that, things work smoothly; after the install, the connection resets (sometimes even crashing the phone) far more often. Has anyone else had this happen?