hi, I am currently having the same problem with Ingress app, on a Nexus5 CM11.
The app uses data regularly but not continuously. When data pauses for a second or two, the data icon changes from H+ to H. I also run Network monitor mini and can see when my phone sends upload/download packets.
Nearly all of the time the phone does not receive download packets while in H mode.
Once it clicks to H+ the download packets arrive and Ingress (mostly) carries out the actions I had chosen.
The cell ID remains the same, so it is not switching masts. Another player on EE with a Z2 has the same issue. There is no issue in 4G.
Where there is low signal strength it can be many seconds before data flows, as I believe the phone/mast is trying to get an H+ connection before using the radio channel, but the H+ is not quite latching.
Twice I have seen H data flow, and in both instances this was after 2 or 3 minutes of zero data on H. Almost as if the phone/mast gives up on trying to get an H+ and allows the H data.
The work-around I have is to use a streaming radio app. This keeps the data flow constant which keeps the H+ connection and seems to help with the issue, though I haven't tested this with very low signal strength yet. Also, this means hearing music when you dont want to (if you want to hear other sounds) but maybe I can make a silent/very quiet mp3 and stream it in repeat mode using another app. (Or get an app with separate volume control)
I've contacted 3 technical about this and currently they want me to swap test my SIM in another phone, and another 3 SIM in my phone to see if the problem stays with the SIM or the phone, but I'm getting the feeling this is on-purpose network design.
