Randomly received new confirmation email? After partner segment change
Does anyone have any idea why I would have randomly received an itineray and receipt from United this morning for an upcoming trip in October that I booked back in July? I didn't request a receipt online, and even if I had, I just noticed that my original receipt from July shows "Method of payment: Visa ending in XXXX Date of purchase: Mon, Jul 11, 2022", and my new email today shows: "Method of payment:Miscellaneous Document Date of purchase: Wed, Aug 31, 2022". I also noticed that my eTicket number has changed, and that the new email shows "Remaining value of your previous ticket numbers 016... was applied to this purchase."
What's that about? "Miscellaneous Document"?!? And why would the date of purchase have changed to today? Nothing else seems to have changed (other than flight times by a few minutes here and there, but those changes aren't from today, as I'd already seen them in the past).