Originally Posted by
iahkid2014
Had a similar problem with an odd twist: attempted to book into the normal (not bulkhead/exit row) E+ section on a sCO flight post 3/3 and the CO site wanted to charge me. However, when booking a sUA flight post 3/3 on the CO site I was able to select bulkhead/exit row at no charge.
Go over the UA and see if your seat stuck.
Sometimes you can do a lot of things, however it doesn't take on the other site!