As far as the rail cars sitting around, that’s common. I was in an industry where i used six 108 ton railcars of sodium chlorate every week, and supply chains being what they were would get nervous if I had fewer than 30 cars sitting around. You’d make reasonable efforts to manage a first in, first out protocol, but you’re not having the spotting crew spend hours getting the oldest rail car. They’d grab the easiest one, until the shipping company started charging demurrage. I’d often have cars a couple of months old.
If there was a clerical error resulting in it not being where the paperwork says it is, then it is missing.