Originally Posted by
Stranger
I have not seen a case where this message shows if P is indeed available.
That's exactly the scenario I'm describing. P was available on all 4 segments (availability unchanged when the segments were "married"), no warning on the website, yet 1 section ends up booked in M on the itinerary.
Clearly a bug during the booking process which was promptly corrected by a competent agent. On the first try.