MM battery optimization + TMobile = radio issues?
Ever since I upgraded my phone to Marshmallow, I was battling an issue with data/signal lockups.
I have an HTC one m8 on TMobile.
Every time I moved around location-wise, my phone signal/data would lock up and require an airplane mode toggle to release and refresh the connection. (lock ups were being caused by the change in data connection. Ex. 4g to lte, lte to 2g, etc)
After a long struggle with radios and roms and HTC telling me to try a new sim card, I finally found out what was causing my lockup.
My phone had been recently discharging faster than normal so I was playing with my settings and turned on battery optimization on Aquamail. (i had turned battery optimization for Aquamail off when the Aquamail settings menu suggested to turn it off to stay on in the background)
After I turned optimization back on, no more lockups. All this time I thought maybe radio firmware or something wrong with my ROM (tried 4 different ROMs) or my sim (which I never changed).
More info:
2 imap email accounts
MM 6.0, Sense 7.0
Build 6.20.531.5
Systemless root (but also happened on full root)
AT&T model phone (but also happened on my broken screened TMobile model)