FlyerTalk Evangelist
Join Date: Nov 2000
Location: Nashville -Past DL Plat, FO, WN-CP, various hotel programs
Programs: DL-MM, AA, SW w/companion,HiltonDiamond, Hyatt PLat, IHF Plat, Miles and Points Seeker
Posts: 11,072
I do not think it has anything to do with B/C ticket. It applies to everyone. They keep adjusting the flight schedules. It may or may not be a good thing that they do not automatically make the new seat assignments if the aircraft changes.
Best thing is to check your online seating on a regular basis.