We are using custom fonts in our project. It works well in Xcode 5. In Xcode 6, it works in plain text, attributed string in code. But those attributed strings set in storyboard
Met the same problem: the attribute font set for TextView in storyboard didn't work in run time with XCode 6.1 & iOS 8 SDK.
This is how I solved this issue, might be a workaround for you:
open the attribute inspector of your textview, change text to "Plain"
click on the cross to delete the "wC hR"(red below)
change text to "Attributed", and then you can set the font and size for your text.