Cannot add time in Parental Controls

Question

I have a couple of computers that my kids use. They have mobile accounts with parental controls enabled on them. One is a MacPro 1,1 with 10.7.5, the other is a Mac Mini running 10.9.1.
When the kids use up thier time on the 10.7.5 machine and they are kicked back to the login screen, I can add more time for them if they attempt to login again. A window pops up telling them thier time is up and allowing me to input admin credentials to add more time.
On the 10.9.1 Mini if they try to login again the screen does the fast user switching "rotate to desktop" animation, holds a second and rotates back to the login window. I am never given the option of adding more time?
Based on all of the other Parental Control discussions I saw, most of how this tool works seems pretty nebulous and very few questions ever get satisfactorily answered. But I am holding out hope that this time someone has a solution. Would anyone running 10.9.1 be willing to see if you have the same issue after a controlled user has used up their time?
Thanks in advance,
Marshall

Answer 1

I have been seeing similar issue since upgrading to Yosemite on our Late 2012 Mac Mini.
It doesn't happen every time, and sometimes it acts differently, more like this:
Dysfunctional Parental Controls
We log into child account. It prompts to add time. I put in my (or my wife's) credentials to add time (we've tried different amounts). It rotates the cube over, shows his desktop for a second, then rotates back to a black screen, or sometimes to the login screen. Restarting seems to fix it, but of course that's not ideal.