I was facing similar problem.
The answer that I found and which I used in real project (but for UICollectionView) was to get the outlet of CollectionViewFlowLayout and to define the margins (line spacing and item spacing) by myself in code.
For example
collectionViewFlowLayout.minimumLineSpacing = getCollectionViewWidth() * 0.05
Where getCollectionViewWidth() is a function, that returns the size of collection view (for different screens it will be different) and 0.05 is just random coefficient.
I hope it may someway help you, you can feel free to ask anything else.
If you have crash when you add margins on any view in your storyboard you can try to get their outlets as well and to redefine their frames. It's kinda bad style, but if you won't figure out the problem its the only one I can recommend to you and which I used myself.
Also try to Clean project by clicking Product - Clean in you task bar when in X-Code.