L40 Ultra mopheads won’t engage

I’m trying to mop with my new Dreame L 40 ultra. The floor space I was mopping in is a tile area in our new church. The mopheads would not go down to the floor level to mop. I checked the mop heads and removed them from the robot. As I was checking to see if anything was interfering with the magnetic connection to the device, I looked at the top of the mops. In the little divot on the mop side I noticed lots of debris. When I removed the debris, it turned out to be metal filings that must have been picked up by vacuuming I had previously done. They were still on the floor from the construction, I assume. As it vacuumed, the metal filings came out of the carpet and off the floor and attracted to the magnetic connection. Those filings must have interfered with the magnetic connection. Once I removed the metal filings, the mop worked as it should.