I have a GA and Cynthia is only giving 20/30

She originally only has 10 quests, so I assume 20 is the correct amount.

They've recently revamped her quests and decreased their number from 30 to 20 for GA users and from 20 to 10 for regular users. They just haven't adjusted the numbers on the sidebar.

Beyond the sidebar having not been updated to reflect the chance (which has been reported elsewhere), this is not a bug. :)