QUICK ANSWER
Check whether the pads are wet immediately after dock washing.
That one observation quickly separates a dock-water problem from a robot-side mopping problem.

INTERACTIVE CHECK
Are the pads wet after washing?
After a manual mop wash, are both pads properly wet?
Still dry after repeat tests?
If dock washing works and settings are correct but the pads repeatedly dry out, use service rather than dismantling the robot’s internal water path.
OFFICIAL REFERENCE
Dreame L10s Ultra mop-pad guidance
Dreame recommends checking water-amount and mop-pad wetness settings, using approved consumables and keeping firmware current.
Open official Dreame guidance