I was just comparing two MP award bookings - one on SQ and one on AC. The AC booking has a link that will pop-up the PNR in Air Canada's system, but the SQ booking has no such information.

Any FT sages know why there's this difference, and which other *A partners will show PNRs on award bookings by United? In my experience, all paid interline and code-share bookings will show the PNR of the partner, but only some award bookings do.