Diagnosis
The mopping pad is either not installed correctly, is overly saturated, or is worn out. The robot is dragging a soaked pad, not wiping.
How to Fix It
Remove the mopping pad plate. Detach the pad. In the SmartThings App, navigate to Robot Settings > Water Level. Set it to 'Low' for most hard floors. Reattach a clean, damp (not dripping wet) pad, ensuring it is fully seated on the Velcro and the plate clicks securely into the robot.
If That Didn't Work
The water tank may not be seated. Remove and reinsert the tank, pushing firmly until you hear a click. Check the tank's rubber seal for debris.
Heads Up
For streak-free results, run a vacuum-only cycle first. The mop cannot pick up dry debris; it will only grind it in.