It's also happening to me in all lots that have a bar. The game lots and the downloaded ones or the ones I made have the same problem. I repaired the game and took out all my mods. But it's still happening, in all situations. Dates or just normal gameplay.
And there's not just the bartender not working, all Sims in the lot just decide to go and ask for a drink. Before this last update, maybe most of them would ask or some of them, but not a bunch of times and not together. They keep waving and asking.
Sometimes, if my Sim goes there and ask for a drink, he'll receive it, but just him. Most of the time the bartender just wave like there's some problem.
Also if my Sim asks for a drink, the bartender start to make it but if some other Sim comes and ask for a drink too, the bartender stop everything and nobody gets a drink.
And the french fries just appear in the Sim hand when he ask for it, but never the drink. I can normally tender the bar and give people drinks.