A dead pixel does occur on some small percentage of monitors and pen displays.
I have not seen it be super common on pen displays from any manufacturer. And none of my pen displays from Wacom, Huion, or XP-Pen have any dead pixels.
It MIGHT be possible to fix a dead pixel
See this video: https://www.youtube.com/watch?v=5pvtiV3B_nE
Usually a single dead or pixel will not be enough to qualify for a return or refund.
If you have a lot of them or a cluster of them, then you have a case for a refund.
In either case there is no harm checking to see if you can return the product.