Yes, in general the most likely source of leaks is a plugged drain tube (there are four of them) coming from the moonroof. Did water get into your door and then into the interior? If so, then look for plugged drain holes in the bottom of the door. If water got into the interior, the first thing I'd check is the moonroof drain tubes, then carefully examine the weatherstripping around the door. I don't know off the top of my head how the 2018 is installed, but for 2017 and older remove the weatherstripping and check that it's evenly "pinched" so that it grips the metal pinch rail around the door opening without any loose spots. Carefully reinstall, making sure it's firmly in place all around. Any areas where it fails to "grab" could allow for a leak.
Finally, also be aware that water can get in somewhere and travel before it's spotted, so the leak might not be anywhere near where you think it is. For my 2009 the headliner was made from plastic and the water was running down the back side and then into a trim molding so the leak was nowhere near where we spotted the water!