Dreame L10 Keeps repeating charging announcement

Hi everyone, I've got a dreame L10 robot. It started acting strange at the dock.
When it docks, it will sometimes say things like "starting to charge" multiple times in a row.

Pls help

Hi, the charging contacts must have some black deposits on it which is causing loose contact Just clean up the metal contacts of robot and station with a dry rough cloth and try again.

L10S Pro Ultra Heat User Manual specifies " Do not place the robot upside down" under Usage Restrictions.
My question is - How do you do the maintenance on the bottom side of the robot e.g on mopping pads, filter, brushes, sensors etc without turning the robot upside down ?