I think the stamina mode is a bit bugged because I notice my apps stop working properly even thou they in the list. For instance, my outlook (emails stop syncing), wechat (can't send or receive anything), or whatapp (delayed messages sometimes). Even if you wake the phone up, the apps is already stopped working so I have to force stop and to start the app again for it work. I think this also explains why the location based WiFi seems not working at times for me too. I turned off stamina mode and the issue has went away.
The interesting thing is that, I have stamina mode turned on family members Xperia T2 Ultra, Z Compact and Z Ultra, it works works fine for them as they have WeChat as well.
Last edited by Sango2; 20th August 2014 at 04:48 PM.