. In the video, Brown smiles for the camera while taking photos with fans, signs a few autographs but doesn’t interact much, or possibly at all, with the fans outside of that. It’s possible that the then-15-year-old was a bit moody that day, as teens are sometimes known to be, but that in no way makes her a brat. Promotional tours are known to exhaust veteran adult actors, so it wouldn’t be a surprise at all if Brown was simply tired from the hectic weeks spent promoting season 3 of her show.
As for the quote from David Harbour, later on in that same piece, he explained, “There’s a piece of me that’s very protective of her and feels that we should all let her be brave and brilliant and turn our eyes away and not give her so much attention.” Perhaps shining a beacon on a teenager is absolutely the last thing that teenager needs to grow up well. This is likely the exact sort of attention that Harbour didn’t want laser-focused on Brown.
Though she’s a very talented actress, which everyone she’s worked with thus far in her career agrees with, she’s still a child. It’s unfair to label Brown as a “brat” over one or two incidents in which the actress was not as bubbly and “animated” as she usually is. There's no way of knowing what Brown was going through that day that might explain her behavior, and it's irresponsible to claim that the reason for Brown's withdrawn demeanor is because the teen is a brat.