I noticed that every time my battery hits 20% and the phone enters power-save mode, my Wi-Fi turns off. If I try to turn it on, it stays on momentarily and switches back off again. The only way I can then turn it on is by disabling the power-save mode. I can understand the power-save mode trying to save battery by turning off WiFi but not allowing me turn it back on is ridiculous. And not having an override option that will totally disable this feature (if it can be called a feature) is frustrating. Anybody else noticing this on their Lumia 920 phones?