WordPress version 3.8.1, Achievements version 3.5.1, theme: Custom Community 1.17.3.1
I was only having trouble with one new user (the community isn’t actually fully live yet, being invitation only for the most part.)
I went to re-test the user that was having trouble at the time that I opened this support request, and the update saved this time.
Consider this resolved, unless I see the error again, at which point I’ll provide as much additional information as possible.
