I've also had issues repeatedly with FAs on some DL flights trying to serve the PDB sparkling wine (usually proseco) in the air and say it's champagne. I can tell it isn't by the taste--I don't need to see the bottle. You should certainly report this. Do you think the FAs were saving it to be a nice "doggie bag" gift, either to the couple or for themselves?

The fact that you had an OPUP is irrelevant; revenue passengers, including those on award tickets paid with miles or upgrades on revenue/award tickets, deserve the same treatment in the air. This is bvasically company policy.

However, do you think the FAs or your FA in particular could have thought/assumed that you were flying nonrev? Nonrevs are not supposed to ask for stuff like drink refills. Especially if catering shorted the flight one or more bottles of the real champagne, the FAs could have been trying hard to save it for weho they thought were the revenue passengers and resist giving it to nonrevs if they feared running out. If they were being proper, they would avoid tellling you it's because you were (they thought) a nonrev as nonrev status isn't supposed to be discussed. Your boarding possibly late and possibly not appearing on the manifest they were consulting for BE could have caused the crew to assume you were an airline employee travelling in BE for almost free as part of employee benefits.