Originally Posted by
The Lev
Broken seat is one reason - if they know that a seat is currently broken on the fin being scheduled they will move you to a working seat. The seat might be fixed by the time of the flight but they don't want the risk of you being downgraded due to a known broken seat.
Downgrade priority does not look at who's assigned to the broken seat. You're just more likely to be moved to some other arbitrary seat.