You make a long, wristy stroke with your shoulders open and elbows are spread too wide. Due to this set up, you probably play the ball too far forward so the face of the putter to appears to be open and you swipe across the ball causing you to slice your putts.
Coming up short with putts when below the hole or unpredictable ball play.
The clubface opening and closing inconsistently to help compensate for poor alignment or because you perceive the swing is completed once contact is made with the ball.
You are worried about getting a strong downhill roll.