As a wood furniture maker, I've sprayed many hundreds of gallons of Nitrocellulose Lacquer. Sometimes, seemingly for no reason, that whitishness appears. It is frequently moisture related, as lacquer dries very quickly and gets cold in the process, drawing moisture from the air. A quick fix, that nearly always works, is to spray pure lacquer thinner on the project, just enough to wet the surface, allowing the trapped moisture to escape. Sometimes that needs to be done more than once. It has saved many thousand dollar custom executive office furniture pieces for me.. Worth a try.