stays: record Yosemite PIN discrepancy

bookings/stays/cabin-yosemite-wawona.md

@@ -35,6 +35,12 @@ the tub; bring toiletries, cooking oil, paper towels, foil.
 with the estimated arrival time and confirmed receipt of the welcome
 information.
 
+**Open discrepancy:** A Booking.com arrival-time email received Sep 18 lists
+PIN `4317`, while the saved confirmation and this record list PIN `5937`.
+This is the Booking.com PIN, not the property door code `0517`; verify it
+before arrival and do not replace the saved value without confirmation. See
+[the recent email source](../../sources/stays/2026-09-18_19_Booking_Yosemite_Emails.md).
+
 ## Sources
 
 - [Booking confirmation](../../sources/stays/Booking_Yosemite_Wawona_Sep22-24.pdf)