HD7 on T-Mobile. I've noticed it seems at times, even if I'm connected to Wi-Fi, the phone still uses the cell data connection instead. If I go turn off cell data, it will then use wi-fi and everything appears nornal.
Is this related to the phone being off or does it happen more persistently?
After enabling Internet Sharing and using it on my Focus the Wifi would sometimes be connected but the phone would still use 3G, worse it would actually 'stall' where no Data would work until I turned off either cell data or wifi and then the other one would work.
If you just notice it when you are waking your phone up, WP seems to turn off wifi when the phone is sleeping.