Today I was searching for flights for an upcoming international RT and saw something that made me suspect I was looking at an "instant upgrade" fare which could cause trouble for MQM earning or during IROPs.

I started with a regular search (eliminating basic economy), picked flights, and was offered a V class coach ticket with a 99 day advanced purchase requirement that I've never seen before. The fare code started with a V.

Then I hit the button for the paid upgrade and looked at the fare rules, which didn't seem to make any sense somehow in that they weren't very detailed at all.

Then I re-did the search asking only for DeltaOne and looked at the (totally different) fare rules. This time the days of the week restrictions were different (maybe that's reasonable for business class versus coach travel) and it had a 50 day advanced purchase requirement, which isn't unusual for a Z class fare. However the fare codes started with X, not Z as expected. The price was the same as the total when I first looked at coach and then asked for the paid upgrade.

The website showed me the 150% MQMs that I would expect for a Z class fare. The X fare rules said business class at the very end and I didn't find any wording about coach fare with an instant upgrade.

However I'm still nervous that DL could try to tell me later that I purchased a coach fare (at a pretty cheap but not unexpected business class price). It's obviously not a mistake fare and everything is DL marketed and DL operated. It looks like the domestic segments are in FC and I don't see any signs of a broken fare or anything else that looks strange.