DIAGNOSIS: The robot is either using too much solution or the cleaning pad is oversaturated and dragging dirt. This is usually a pad or tank issue.
FIX: First, ensure you're using the official iRobot Braava Jet cleaning solution, diluted correctly with water in the tank. Do not use vinegar or other substitutes. Second, use a clean, dry pad for each job. For heavy cleaning, use the damp pad mode, not the wet spray mode. Wring out the pad thoroughly before installing if using reusable pads.
IF THAT DIDN'T WORK: The spray nozzle might be clogged or leaking. Remove the tank and inspect the small black nozzle on the robot's underside. Clean it with a pin. Run a clean water cycle without a pad to check spray pattern.
HEADS UP: Overfilling the tank above the MAX line will cause it to leak excess solution directly onto the pad, causing immediate smearing.