Are you talking about this circled bit?

If so, this looks fine. It's just used as nailing surface for drywall -- it's not structure. It kind of looks like someone made the bottom of it a bit short, and then built that end piece to make up for it. Worse is they made it not quite wide enough, but again, it's just a nailing surface.
Being generous, maybe that's made from leftover wood, so they were actually saving you money by not paying for another full length piece of lumber plus paying to throw out the scrap, just to prevent an irrelevant <1" gap.
A "header" is the part above a door or window (and important to get right because it does support structure and weight), but I don't see an issue with that.