The robot creates a map, and it works normally at first. However, later on an overlay effect starts to appear (maps are overlaid onto each other, and the layers are misaligned). What can I do?

(1) Do not physically move the unit during cleaning, otherwise it will cause a relocation error that muddles the map.
(2) If you have overlaid maps, go to the More page in the App and manually select Reset Map. Then have the unit start from the charging dock to create a new map.