Had cocktails at bar before dinner with colleagues and customer. Ordered a Mum Napa champagne split at the bar with cocktail server #18, which was wonderful and have had many times. Before cocktails were done we were shown to our table. I ordered another Mum Napa split when seated. The dinner server came and was telling us about the menu and chatting with us. During this process cocktail server #18 brought my champagne and set it down. After the menu process with our dinner server, I noticed there was not a split bottle next to my glass(it usually fills glass with some left in bottle) but didn't think much of it. I took several sips of my drink and noticed a big difference in taste and not having the bottle I was pretty sure it wasn't a Mum Napa but maybe the Prosecco that is also offered. When cocktail server #18 came by again, I discreetly asked her if this was a Mum. I did not want to make a scene or anything close to that with business colleagues there. Cocktail server #18 said indiscreetly, "you saw me pour it, it was a Mum". Whether I saw her pour it or not was irrelevant. You do not respond to a customer with a comment like that and a tone of voice like that. I actually do not remember her pouring it with everything that was going on at that time and maybe I would have if the bottle had been left with remainder of the Mum. After that encounter, cocktail server #18 became pretty condescending. They did take it off the ticket which they should have because it either wasn't a Mum or it was a bad split bottle. If I heard one of my employees talk to a customer like that, they would be dismissed or put on "cleaning the wine glasses" duty for a week. Otherwise, the food was fine, the dinner server was great, and enjoyed being with colleagues and friends.