Customer had staining around vent below upstairs primary shower. Customer showed video of water dripping through. This occurred when the shower was on and unattended so that path the water took is unknown. Checked the trap and it’s still holding water. Customer just replaced the shower head, so tested the vertical riser and shower arm by removing the shower head, installing a cap, and turning the water on. No water leaked from the vertical riser or shower arm. Next, removed the drain cover and stopped the drain up. Filled the fiberglass pan with water and let it sit. Still no water leaking from above. Finally, released the water and drained a large amount of water rapidly and no water leaked. Noted two areas, each at the corner of the sliding shower door, where there was water damage in the drywall and wood. Made customer aware that water is likely leaking near the corners of the doors and getting past the seal and around the shower doors due to a lack of sealing. Recommended having th