Question: phone doesn't get locked properly while on call
Iphone-6s doesn't get locked while call is going on-- if i am using a headphone and the phone is stationed on my table and while on call i lock the screen using the sleep/lock button and the screen gets black but when i move the phone the screen reappears once again and all the buttons related to calls like call end, keypad, contacts and mute etc. are active and inadvertently if i touch the end key the call will get terminated. This issue was not there in 5s. While on call the screen if once locked should require pass-code or fingerprint to get unlocked.
iPhone 6s, iOS 11.3.1