Why is my signal strength indicator sometimes not a continuous symbol? When this happens the quality of my phone calls are not as good as in normal case and sometimes it even hangs up the phone call.
As far as I remember, this is a bug related to 4G (LTE). I think several users confirmed that the loss of (telephony) connection disappeared when they went down to 3G only.
No idea if this is being tackled in the current development on Android 7 for FP2.
I still face this with these icons on Android 7 beta, but only while I’m calling. I think, even though I call on SIM 1 and have data with 4G on SIM 2, the phone is downgrading 4G to “something else” while calling. Actually I don’t have access to any data at all while calling. This behaviour hasn’t changed from Android 6 to Android 7.