Something similar happened to me and my husband recently. I don't know whether it was "IT" or something else, but on an E175 we were moved from 6C/D (next to each other) to 6B/C (across the aisle from each other). There was no way to move us back together and keep row 6.

There's definitely something strange going on with seating at AS, and it's frankly annoying. I shouldn't have to keep checking my reservations to make sure I keep my seats.