Blades may leave haze due to residue or buildup on the windshield. Cleaning the glass usually resolves this.
Windshield wiper blades could leave haze if the windshield is dirty or if the windshield has a water repellent coating such as the one in Rain-X Latitude Water Repellency, Rain-X Repellency, or Rain-X Quantum Elite Wiper Blades. For water repellent-treated windshields, initial hazing is normal and should disappear with wiping or washer fluid.