I have used 5200 for years. This has always been my favorite sealant, be it on my boats , around the house, or general repairs. This last tube I bought however, did not make me very happy. Over three days to dry/cure. this was indoors.  I am assuming this is a very rare exception as this has never happened to me before. Like I said , I have used this 3M product for years and have always recommended this as a ,  pretty much ,  permanent flexible weld. Well worth every penny .  I will assume it was produced on either a Friday or Monday.