When I am using the system Messages app and in a conversation with someone, I seem to sometimes activate some kind of shortcut in which it begins to call the person? I've noticed it tends to be when I move the phone in a certain way, but I can't replicate it when I move the phone. My phone touch screen is working fine, and I am definitely not pressing the call button in the top right corner.
There's another option that you might consider. Direct call is designed to automatically call a contact when you're in a messages app conversation. It's designed to use the motion of bringing your phone up to your ear. It's possible it might be misinterpreting a motion when you're in a text message conversation.
On my S9 it's located in settings, advanced features, motions and gestures. It might be worth a look.
