http://www.flyertalk.com/forum/unite...r-profile.html
In the above case the glitch was three days. Curious.
And yes, I just checked my united.com profile, and it too has me as a day older.
Edit: a few days after reporting this, and uploading an image of photo ID, it is correct.
I think what triggered this is using the app to book award tix. I have noticed since May of 2013 that it was using the day prior to my actual dob, but united.com had the correct DoB.
In the future, when using the app, if I see it loading the wrong DoB, I will create a companion profile with my name and no FF number, and use that instead.