I couldn't find any reviews or reports to that effect, but this model is also fairly new. Ultrabookreview has an article from November this year:
https

/www.ultrabookreview.com/16539-asus-vivobook-s510/
... but they make no special reference to any brightness problems. They do recommend using a calibration program that can be downloaded from their web site, but that doesn't necessarily signify specific screen issues. In short, the screen is OK for an IPS panel but not amazing.
Techarp has a YouTube video and a corresponding article that don't really tell you anything except that the ASUS looks great:
https

/www.techarp.com/reviews/asus-vivobook-s15-s510u-laptop-review/
And then there are dozens of videos from Thailand, Malaysia and...