Is your email address from a "free" service like Gmail? If it's not, is your email run by Google through their G Workspace (formerly known as G Suite) service?

Different mail servers handle prospective SPAM differently. I have my own domain I purchased just for email. I used to run it using Google as the mail provider. I had problems that were similar to what you mention. I switched to a different mail server provider and the problems disappeared.

If you have access to multiple emails, try changing the one you're using with JetBlue. It may take a few weeks/months, but you'll be able to figure out if the problem is on your side or with them.