I always assume that haze that appears when it shouldn't is contamination. I'm not saying that's always what it is, but since I don't have a microscope or staining, I can only guess. I doubt that protein got in there, or new hop polyphenols, so if I assume it's a contamination my reaction will cover anything else it might be. Dump, thorough cleaning, thorough sanitation... maybe even sterilization if it's parts that would survive my autoclave (pressure cooker).