ios - Whose View is not on hierarchy -

i getting error swift , unsure why there 1 view controller has occurring error view in not on hierarchy. question why occur 1 of view controllers presented primary viewcontroller button not other view controller linked primaryview controller? there cause occur specifically. trying present modally , being called programmatically can pass data objects.

for me seems strange occur 1 viewcontroller presented viewcontroller not other. thing did didn't think effect duplicating primary viewcontroller again why 1 work not other? problem happening ios.

should have checked buttons make sure linked correctly. realized after reading few of same questions should check button selectors under view controller references tab see linked what. had 2 actions doing 2 different things 1 button accident must have miss clicked control drag function.