Welcome to Android Central! What do you mean by in-call lock? When you're in a call, does the screen stay on with a lockscreen which you have to double-tap to get back to the dialer? This is typical when a phone either doesn't have a proximity sensor or if you turn the sensor off -- it's meant to prevent you from accidentally pressing any onscreen button with your face when you're on a call. If the phone didn't have a proximity sensor in the first place, you typically can't turn this off. If the phone does have a proximity sensor that you can turn off, the setting is usually in the Phone app's Call Settings.
If the phone does have a proximity sensor that stopped working after the screen replacement, bring the phone back to the repair shop and ask them about it.