I had this problem once or twice. Hasn't really been a consistent thing for me. I run pretty thick grips (Scale grips from Shooting Sports Innovations). You can try thicker grips, but they're only gonna get so thick. I would practice the way I grip the gun more. Try and really get a consistent grip where your right thumb rides over the safety (assuming you're right handed) and keeps it down. Sent from my SM-G950U using Tapatalk