You can simply install a WiFi access point so the phone doesn't need to be tethered to your PC. I know it's more of a work-around rather than the solution, but at least it will accomplish what you want without running into the bug.
FWIW, I never use internet pass-thru. Instead, I either use WiFi or my data plan to connect the phone to the internet. On occasion, the phone would stop connecting to either connections (WiFi and 3G, HDSPA, EDGE indicators are off), unless I toggle them off then on. Yes, another bug I'm afraid.