Xperia M5 DUAL AND XPERIA XA DUAL wifi turning on

[anubesideu]

After the system update my phone software changed to Android 6.0. I'm facing a problem while using WiFi connection ie whenever I'm using Internet through WiFi mobile data also getting "on" and balance also going down.
My friend also facing the same difficulty in xperia XA dual which is also a android 6.0.
Kindly pls go through the mail and Fix the bug as soon as possible.

[Uliwooly]

If you have WiFi on, and you still see the data icon (3G, 4G LTE) then it means that either the WiFi isn't connecting properly or you are sending and/or receiving MMS which will only go through your data. 

[anubesideu]

All the time I'm using external WiFi, I have switched off the mobile data of the phone. by the time mobile data automatically go on and consuming the mobile data of network provider.

[Uliwooly]

This has been reported before with other Xperias, and it seems that the carrier/network re-enable the data 

[Nishr]

Even i am facing the same issue with Xperia XA DUAL.
It has Android 6.0.

Network provider is not taking any complain as this is cellphone issue according to them.

first time sony user..  
seems will last by this.