I've been attending the developers summit this week, and sitting in Arcade sessions when I can. I'm messing around with the Map Viewer Beta which as I understand it, will no longer be beta next week.
The label/Arcade Editior makes it pretty easy to create a label, but it's a little weird at the same time.
In the list of globals, some of the field names are in brackets and quotes and yet others are not:

So when I select them, my expression looks like this:

And it's flakey: it tests okay, but sometimes I get labels and sometimes not.
Has this bun been in the oven long enough to come out of beta?