I've been noticing that sometimes after using WiFi for a while then turning it off and going back to the mobile network, apps using data won't work although the data icon is present. I've gotten it to work again by putting the phone into airplane mode briefly, then turning airplane mode off. This seems to re-initialize the network connection without having to reboot the phone. Any ideas on why this happens or how to fix it? Phone is rooted but I haven't changed anything that should cause this, all stock and no custom ROM installed.