I may have stumbled upon a new use of married pair logic on the UA web site.

I'd planned a spring trip to Hawaii for Mrs. Transportprof and me on the same PNR, and selected our seats in E+ at booking.

Then we decided to invite our niece along, and I booked her a ticket on points. No more inherited status for her seating, so we have to buy her E+ to sit together.

When I look into the pricing it turns out that the middle seat in our E+ row costs $6 less than the aisle or the window. So I figure that I'll move myself from middle to window on the 737 and buy our niece the middle seat. No can do!

When I move myself from middle to window, Mrs. Transportprof is automatically moved to the middle seat. It appears that it's no longer possible to sit with an empty middle between two E+ seat bookings, at least when they were booked aisle/middle to begin with.

Given the massive wait times to reach an agent on the phone during the recent blizzard, I just went ahead and paid the extra six bucks to buy my niece the window E+ seat in our row.

Anyone else come across this pairing lock on seat allocation, at least in three seat Y rows?