Network drops

[pvnsai73]

In 4.4.3 kitkat the network is fine... But when I upgraded to lollipop (5.0.2,5.1) Im facing some weird problems that some network goesoff and again automatically it's back aftersometime...I have replaced with new sim card though the problem still occurs but the simcard is working fine in other phones.... And mainly this problem only comes with "idea network" remaining all networks r working fine in my phone

 

[unnonymous_3]

I had the same problem. When I used:
Sim 1 -> GSM only for phone calls
Sim 2-> WCDMA for calls and internet

The problem occurs while placing a phone call. I hear a beep during the call and both networks are restarted leading to a drop in the call and 5 seconds until the networks are back.

I swapped the roms in terms of connectivity and switched my data plan to the other sim card, so:

SIM 1: WCDMA for calls and internet
SIM 2: GSM only for calls.

Now it is working perfectly fine.

To me, it seems to be a bug in the firmware that it triggered by some networks while on the dual mode.

Hope this helps you,
Good luck