I recently booked the following itinerary, MAN-LHR-JFK (in premium economy/euro traveller) JFK-LHR-MAN (in J).
As a lowly blue, I paid for seat selection on the two transatlantic legs but Immediately after booking the itinerary I could select a seat for no cost on the LHR-MAN leg of my journey. I'm curious as to why and wonder if this is BA's IT playing up, will the seat reservation disappear at some point? I don't really care if it does as its a <1hr flight but thought I'd ask the question.