Probably it isn't what you expected to get as an answer
Group label not showing up in NodeBB vanilla theme
I'm not sure if this is a bug, but in the current version of NodeBB Vanilla theme, the user's group label is not showing up anywhere in posts or is it supposed to be like that?
The group label wasn't added in to vanilla. I personally had a look to see where it could go, but with the first post and subsequent posts being different, it wasn't easy. If you want to add it to your own theme, the code is between line 48 and 54 here.
If you find a good place to put it that works reliably, maybe make a PR for anyone else that uses vanilla.
Oh I see...
Anyway thanks for the heads up!