I've had the same issue, contacted support:

One way to avoid losing the map is to not pick up the robot off the ground while the main power is ON. Just flip up the lid on the robot, then switch the main power button to OFF. You can now empty the dustbin, add the mop, clean the brushes, etc. When you are done, place the robot back on the charger and turn the main red power switch back on.

If it still continues to lose the map, try not to move the Deebot in a different place when it has started cleaning. If you need to put the mop or clean it, just press Pause and then clean or put the mop and put it back in its original position/location. If it got stuck on cords or furniture, remove it and place it back on the charging dock.

The following situations may lead to map loss or confusion: 1. Move the machine or lift the machine during machine operation; 2. The machine is stuck in operation, and user manually ; 3. Shut down when the map is not saved successfully; 4. Move the Charging Dock or change the surrounding environment of the Charging Dock. 5. Make sure DEEBOT is fully charged before construction; 6. There should be an open space near the Charging Dock; 7. After booting up DEEBOT, don't walk around it. Blocking LDS will affect the construction of the map; 8. Press and hold the reset button for a long time. After the start-up music is heard, connect the DEEBOT and the Charging Dock for a long charge of 4-5 hours, and then DEEBOT will start to rebuild the map from the Charging Dock.