DC was famously unhappy with Jack "King" Kirby's rendition of the Man of Steel. You'd think that giving a proven talent like Jack Kirby a title like Jimmy Olsen would pretty much indicate carte blanche with the approach, but it was not to be. DC conspicuously kept its editorial hand in and infamously used artists Al Plastino and Murphy Anderson to alter the Kirby Superman heads to make them conform to DC's then standard house look. Those alterations were jarring at the time and still stand out in modern reprints of those stories. I'm generally speaking a fan of blending artistic styles, and frankly would not have had any big issue having Anderson ink Kirby's work, but just altering the heads really made them stand out in a weird way.