Android’s KitKat operating system ended its data connection once an app completed its transaction but Lollipop (5.x) doesn’t do that. Data access remains enabled long after an app has finished doing whatever it needs to do … and this is why Lollipop users get so much battery drain.
As this issue has been reported over 3000 times to Google, it will be fixed in Marshmallow (6.0). But this means we’re going to wait a while.
My theory is: Google keeps the connection open the better to track us with, my dear. By the time Google rolls out a new OS, I guess the company will have all the data it needs to successfully intrude in just about every aspect of our lives, God help us.