Bad offset at first launch

[iNono22]

First time I try to use this in my project. I always have this weird offset at launch. After I scroll the collectionView, it pings right but not at beginning

[iNono22]

Update: When I am at the top I have a weird jump at the end http://jmp.sh/Zdzuztb

[famictech2000]

@arnaudWasappli have you implemented the functionality where a user can navigate to a "Detailed" view, when they click on a specif cell and then dismiss the detailed view to return back to the collection view?!