I had 4 replacement monitors (P2415Q), they all had this issue.

P2415Q display oneP2415Q display twoP2415Q display threeI just can't reconcile with a fact that Dell made this kind of omission.

I have another Dell display which I use for a long time, and it's impeccable, which made me consider Dell as trustworthy and reliable display manufacturer. But buying a premium 4K monitor from Dell and doing four replacements, one after the other, with current fourth (manufactured May 2020) display, having exactly the same issue, and then some other issues like yellow tint on screen edge is truly disappointing.

I worked in computer hardware store which among broad assortment of computer hardware,
sold second hand computer gear, never saw (or heard of) cases like mine. I'm disappointed that Dell has this kind of issue, and does not provide official explanation for this fiasco.