When you 1st logged into the WiFi signal, did you click the box "connect automatically?"
if you did, it will log into that channel anytime you are near it, AND the WiFi is up and running.
I control such things by turning off both DATA and WiFi manually when I lock the phone.
actually the WiFi is done automatically with a macro.....
With 4.4.4 and earlier, the macro did the same for DATA, but no more, unless you root your phone.
back to your problem... if the DATA and WiFi are turn off, they cannot log in, period.
as for logging out? that is a "Loss of Signal" issue most likely.
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