FWIW, here’s an update about my issue. After the pending charge was sitting on my American Express card account for about five days, it suddenly dropped off. There’s no trace that I ever made the $60 purchase for the two checked bags with JetBlue. So I’m guessing that it’s another technical glitch problem with the JetBlue website. I will go ahead and try to purchase those checked bags again, probably with an agent via chat to make sure it gets processed.