I am using three commands like the following one, using status icons. As i recently found, they appear to be broken in Beta 12.0.15. Assigning those labels per menu still works, however. Since the fix list for 12.1 doesn't mention it, i assume that the issue still persists.
@nodeselect
Set Columnsadd=Status(1)
Properties SETLABEL=Flagged ADDLABEL SETLABELTOGGLE
What exactly do you think doesn't work? It seems to do what I would expect.
The labels just don't show up here. All that happens, if i turn off the status column, is that the command would turn it back on. But the labels are not applied. It must have worked in the older betas, though. I was using them frequently.
Is your "Flagged" label still there in Preferences / Favorites and Recent / Labels?
What happens if you run the command twice? (Maybe the file already had the label, and you're toggling it off, since SETLABELTOGGLE is being used.)
Does setting the label using the default toolbars/menus work correctly?
Why are you still using 12.0.15 beta and reporting issues on it when 12.1 has been out for two weeks? 
Yes, i have checked that. They are there, all three of the standard labels, plus two own ones. I have also checked, if the commands would work from a button (usually i set the labels using hotkeys), which they don't.
If i run it twice, still nothing happens. As i said, things worked fine in older versions.
Yes. As i mentioned, it works from the right click menu, & also from the toolbar menu, which i normally don't use that much. Bot both work.
Good question. I am receiving some licence for the official version these days, which i require to update to the new official version.
I forgot to mention, i was chosing files, where i was sure, they did not have any previous status label. I have also turned on the label name column, to see, if maybe they are just not displayed for some reason. Which was not the case.
Sorry, i misinterpreted the info box in the version 12 installer, overlooking the part with the expiration period, which still allows me to update. I have now installed the latest version, but things are still the same.
For me the name of the label must be Flagge not Flagged to get your command working:
@nodeselect
Set Columnsadd=Status(1)
Properties SETLABEL=Flagge ADDLABEL SETLABELTOGGLE
Damn, you're right. Things are back to normal. I also figured the other keyword, "wichtig", for "important". Now i only need to find the right translation for "checked"!
checked = markiert. You can look up the label names in preferences.
Now you have mentioned it. I previously had checked, if the labels are present, but didn't think about the translations at that point, that they also have changed in the codes. Thanks @all!