I downloaded the plugin today May 25, 2016 including the PRO version and having the same issues saving settings.
I can save the settings, and they apply and get used functionally, but they don’t display/keep on the settings page.
This is slightly annoying because if I go to update any single setting in the settings page I have to remember to update ALL of the settings to what I last had them set, unless they essentially re-set.
Not urgent at the moment but as I migrate my clients site to live (where they can update settings) it will be an issue.
Would love a fix.