i have a **uicollectionviewcontroller** as **rootviewcontroller** in my navigationController. whenever i return from another controller that is pushed onto this stack. the collectionview jumps up 25pix. i have tried some tips from other questions like **self.automaticallyAdjustsScrollViewInsets = false**, changing **contentOffset** after collection appears but none of them work.
i have no idea what causes this problem.

[this is a sample off whats happening](https://i.stack.imgur.com/qwWVW.gif)