You're still leaving details out. It sounds like you're saying that your many past UA boarding passes have had TSA PRE on them, but now you've gotten one that didn't. Is that right? What do you think changed? I'm guessing your name has always appeared without the apostrophe and hyphen in United's records.

The representative you talked to -- was that a UA rep or a TSA rep? If UA, most likely the rep took a guess at what happened.