You may be the first person who's tried to change profile information since the upgrade. (You're the first person who's brought this to our attention, in any case.)
I looked on the help site, and this is a known bug with the software. Unfortunately, it needs a change to the source code, which I can't do.
It will allow you to change the birthday in your profile, though, as long as there is a valid entry in each field (day/month/year) and not "---", the default selection.
I entered Jan 1 1908, the oldest date in the list. Please feel free to enter junk data in the birthday field, if you need to change your profile, but please do not choose 1994 or later, since that would suggest you are under 13 years of age, which is in violation of COPPA, as I have no signed permission slips from anyone's parents (16 being the cut-off for membership)

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