Out of curiosity do you have any upgraded (YBM, CPU or instrument) or waitlisted segments in the reservations?

The new website has major cookie issues with IE (on my work desktop, work laptop, and home laptop) where it will "forget" who I am after loading the itinerary summary and error out on literally anything after (e.g. change seats, change flights, view receipt...)

OTOH, in Chrome I've had no problems changing flights except for those reservations with segments booked in B and instaupgraded to PN and an award reservation where I was booked XN but waitlisted for IN before deciding to go a different route (figuratively and literally). I think the B->PN issue has existed for a while, bout I don't remember it being so annoyingly consistent until the new site rolled out.