Wrong top inset when adding header to collectionView

[foffer]

Please refer to this SO question to see the issue http://stackoverflow.com/questions/41570814/gap-between-headerview-and-collectionview

I believe this to be a bug, since I have not asked the CollectionView to apply section insets. If I implement the insetForSectionAtIndex delegate method, nothing happens. Let me know if I can provide further code or explanation to help.
I think the erroneous code is around here: https://github.com/chiahsien/CHTCollectionViewWaterfallLayout/blob/develop/CHTCollectionViewWaterfallLayout.swift#L227

If i print(top) and run my app, it will cycle between returning 414 and 0.

Update

I believe I have found the bug. For some reason this line here https://github.com/chiahsien/CHTCollectionViewWaterfallLayout/blob/develop/CHTCollectionViewWaterfallLayout.swift#L225 was set to maxX and not Y. Dunno why this has happened, but I figured it out now :)