I'd like to recommend creating a account so me or other members can assist you, as guest have limitations in replying here and if we need further Information to communicate with you.
If it's happening when you're not on a phone call, it's probably a firmware problem, because it's supposed to be ignored unless you're on the phone (or you're running an app like Proximity Service).
I'd like to recommend creating a account so me or other members can assist you, as guest have limitations in replying here and if we need further Information to communicate with you.
Welcome to Android Central! Do you have a case with a flipcover? If you do, and it's not an official Samsung one, it might not be designed that well and could be triggering the phone's auto-sleep feature intermittently (making it think the cover is closed). This could cause the lockscreen to show up subsequently.