I bought this phone 3 months ago and have been going through 2 major issues which have become a pain in the **s.
1) Most of the times, while making a call the screen freezes and the timer is stuck on 00:00, and the UI stops responding to any inputs, which means i cannot use In-Call features. If there's a need to make another call after the previous one then the phone needs to be locked and unlocked since the UI doesn't respond to anything without lock/unlock trick.
2) This one is more annoying and it's about Wi-Fi.
When I connect my phone to the wifi and leave it idle for say 5-10 minutes (provided there's no data being exchanged between the phone and router) and then try to open a website, it just doesn't open it with any browser and all other applications which require internet access stop working.
I have tried changing routers and even tried keeping my phone next to the router but the problem still remains. STAMINA mode is always disabled and "Keep wifi on during sleep" is set to "Always" and "WiFi optimisation" option is also unchecked. To make it more clear, the wifi icon is still displayed after idle time of 5-10 minutes on the top right corner with the uplink arrow lighted up and the downlink arrow not lighting at all.
Please reply if somebody else has the same problem and has any solution to it.
I am on stock ROM, with the latest official update 15.3.A.1.14, everything as it is.