For those providing data points, I think it'd be helpful to make sure we include:
- Booking channel (DL.com vs. phone vs. OTA vs. corporate TA/portal)
- Status, though I assume this only impacts PM+ who can upgrade at booking
- Whether the C+ upgrade box is checked in your profile
- Whether your flights showed "UG available" on the flight selection screens at booking, if you checked
- Outcome: If you were auto-upgraded, when the UG occurred if it happened, if you had to intervene at all, etc.

If external booking engines are ignoring profile preferences, that could be quite annoying as it's forcing a choice that not everyone would make 100% of the time.

I'll go first:
- Booked through corporate portal (Egencia)
- PM
- UG box unchecked
- Flights showed UG to C+ available
- Was not auto-upgraded, but after ticketing noticed that both UG boxes were checked within my reservation. Had to uncheck, submit, re-check, then submit again in order to get the C+ UGs processed. I did all this within 10 mins of booking - not sure if the C+ seats would have cleared on their own later, but I wanted to go ahead and select the seats I wanted.