Perfectly normal. It proves to you that it is behaving like it should and that it IS switching to wifi. Your policy is set to "only when plugged in"
If you don't want this to happen, set your wifi policy of keep wifi on during sleep to "always"

 

Even if you set it to only when plugged in, you wouldn't rack up data usage when your screen is off and you are still in range of your router as the wifi connection would take priority for any background activity requiring data.

Not sure why your icons switch over if your policy is set to always. I can only think it might have lost wifi signal temporarily.

 

Not necessarily. As you say you have the "always" option set in the wifi advanced settings then It just proves that your phone has dropped wifi connection and during this time it did not request any external data.

Your phone is set for wifi to sleep when screen is off...somewhere. you must have some 3rd party app (eg. Juice defender) that is putting wifi to sleep.

Even so you will not be using any data during this time as long a your router is on and you are still within range. The only time data will take a hit is if you actually turn off wifi on your phone, or turn off your router.

 

I am fully aware of what you have set it to. I EVEN MENTIONED IT IN MY PREVIOUS POST. (I can write in caps too!!) You do not understand what i am trying to say to you. I think another app is putting it to sleep and your phone did not request any data prior to you turning your screen back on. How do you know it didn't connect in sleep? It may have done so several times during sleep, and that it just so happened it was in sleep mode prior to when you turned your screen back on.

If you don't have juice defender or similar, Another thing to consider is do you have power saving mode enabled? This might be putting wifi to sleep particularly if you have defined custom settings and your battery is below a certain level.

If you don't have any of these things set, then i don't know I'm sorry.

 

That's because your connection had been dropped and your phone is instigating the reconnection process automatically. This is what would happen when sleeping and an app requests data.

Something is putting your wifi into sleep. If your sure it's nothing on your phone that is doing this then i suggest to have a look at your router settings. Perhaps there is a some sort of connection dropout timeout in it's settings

 

Power Saving mode on the wireless router can cause this behaviour. I know that some Netgear routers, for instance, have this... as well as other models.

 

When your wifi is sleeping on your phone, you will basically see the 3g icon on your status bar, as when you wake up your phone it will take a second or two to get the connection set back up.

So in this sleep state, when a background app requests data (eg. Sync, weather etc) if you could see the screen this is what you would see...your phone re-establishing the wifi connection in order to send/receive the data.

When you turn your screen back on, all you are seeing is your phone reconnecting to your router.

now I only see this happening if i set my sleep policy to "only when plugged in". I've not seen this happen on "always"

So like i said, if your adamant some setting or app on your phone is not setting your phones wifi to sleep, then start looking at your router.

As long as you are in range of your router even in sleep state you won't incur any data as wifi will automatically reconnect.

 

It's not going to disconnect if a "mystic" app requests data. On the contrary, it would enforce a reconnection if it happened to be in sleep mode at the time.

 

But it is not failing. In Your first post you said you see it's in data mode temporarily when you switch the screen on after which the wifi gets turned on. Why do you consider this to be failing?

 

You didn't say data always stays on even in wifi range. You said once the screen is turned on it turns wifi on. Ergo "temporarily"

 

So when exactly do you see wifi turning back on in your statement in post 1?

 

so you got nothing to worry about then.