I have discovered that when the membership plugin is active, my featured slider does not display the correct pages. I have the theme set to pull 4 pages. It pulls the first two correctly, but the second two it pulls randomly instead of the two I've assigned. This happens in every browser except Chrome. So you can look at it in Chrome to see how it's supposed to be, then look at it in Firefox to see how it's incorrectly pulling two wrong pages.
I contacted the theme developer, and they looked into it and said to contact you.