I have seen similar from trucks washed with a soap meant for being used on class 8 trucks buy fleet washing services. Usually a high acid concentrate that's supposed be run through a power washer and be highly diluted. How I know we have a 30 gallon drum of it we use to wash the rubbish truck bodies only (high concentrate in areas covered in thick trash juice). This stuff can destroy a paint or clear coat very fast one wash will strip every once wax ever put on a car and can even cause streaking if left to dwell at all. I only use it on the really slimy dirty parts of the truck or as an engine degreaser, but I did make the mistake of using it on my rims a few times one winter trying to remove rust stains (now I know about Iron removers), few months later clear coat failure all over my rims. Could be straight oxidization but I have seen that on some the hoods on our trucks that I know some the idiots working here must used the wrong soap on. Got trucks from same year same manufacturer nearly twins one still looks ok light oxidation other looks like its 10 years older heavy white chalky oxidation.