Had this exact panic recently for 3 Avios redemptions on JAL in May. Nowhere to be seen anywhere in MMB nor an email receipt. Only way I could find them was by searching with PNR which I had saved when the booking was confirmed. Glad I make a habit of screenshotting the confirmation page at booking.

These were booked in November 2024 so it sounds like the issue has been going on for a while. Basic things and all that...