Apparently I wrote a check for that setup (or enough of them for all of us) without realizing it.
I just keep enough in there to cover autodraft bills but I think I would remember writing that check.
I had this issue after my wife passed. I closed her savings account, and it triggered something in their system since she was also on the joint checking. I had a bunch of money in there, but they did something to make it show up as the same as yours. I got it straightened out, but it was the same day I was leaving for WY and I needed cash for the trip.