How quickly are you on them about these things? Are you telling them to put the milk away when they’re tidying up their bar after making drinks? Or are they turned around doing something totally different? They may not be as fast as you or have a different order in which they clean up. Best bet is to stay in your lane and don’t micromanage your coworkers, it creates a toxic work environment. Just tell your supervisor about your concerns and they will deal with the behavior because thats part of their job.

Get a shift or manager to come back you up when yoh say stuff like this, or if you do and it gets disregarded, then go get one to back you up afterwards. From what you have said those two things are both right.

Umm shake the tea always. Even if it’s no ice, no water. But also if they’re not taking your coaching well, just bring it to the attention of a higher up. Hey i noticed so-and-so consistently making XYZ error(s) and i tried coaching them on it but they didn’t receive it well. Maybe you could bring it up to them next time you notice it?

I mean if they’re on bar and you’re not, it’s sort of on their own head be it - as long as they know alt milks are supposed to be kept in the fridge and they’re choosing not to, let them. If you’re not being paid to supervise them, don’t.

Also, in the Spring 2021 update, we were told teas aren’t to be shaken anymore (UK at least).

One way you could encourage it is by saying hey, is there anything you’re noticing that I could do better? Maybe they have and just wanted to stay in their lane and preserve the relationship with you. It could help develop a culture where you’re all more open about doing the best you can do. At mine we’re so understaffed and time pressured, no one is criticising anyone - we’re just grateful they came in.