Annoying bug but fixable. I also encountered it in my no mods and cc savefile that I have for testing the bugs myself. All you have to do is turn the cheats on (shift+ctrl+c) write testingcheats true. Once you enabled cheats, hold shift and press on the barista, you'll see "reset sim (debug)" option. Press it, it resets the sim and they do what they were supposed to do. The same thing works for sims standing and doing nothing. Reset them, then make them do the same action again and they are good to go.
This is how I fix the bartending bug as well. Sometimes when simulation lag gets big it doesn’t always fix the standing around issue- but that’s a different topic.
