This is a carrier well-know effect after the big adoption of smartphones around the word.

As we explained in previous sections, each time the network decides to move a handset from one state to another is needed to restablish channels and starts a negotiation between the network and the handset with the signalling protocol.

Since nowadays handsets are sending keep-alives to maintain their connections opened, the efect is that the handsets is continously changing from one state to another producing a lot of signalling in the network and also consumes a lot of battery resources.