Broken Android OS or Build

[chuck stein]

on moto-x, v5.1 ATT build LPA23.12-21.1

G Play settings say wifi only
i turn off wifi and app updates come down over cell network !!

been constantly reaching over cell data limit ever since upgrade to lollipop v5.1 from kitkat

 

[Hadron]

Turn off automatic update of apps. That way you can be sure you have WiFi on when the update downloads.

Only a workaround, but I don't have that phone and haven't met the problem, so it's all I can offer.