One of my primary complaints about US passports began when the shift took place whereby the government lost the plot on how first and/or even middle names can be family/surnames while last names may be given names. The disconnect between the titles on the application fields and the pre-printed titles on the passport blanks hasn’t made those kind of situations any better. The way some deal with this to try to have a higher PreCheck approved rate is to sometimes use a different ID than the US passport, but that may get somewhat messier too as the TSA increasingly shifts to ID scanning to pull up the PreCheck status for the presenting flight passenger.

Leaving out the middle name from the ticketed bookings often has no impact on PreCheck approval even when the middle names show on the ID being used for the travel document check by the TSA when PreCheck passengers are trying to head airside.