native iOS app not respond after return from unity to iOS App

I integrated unity my swift app.
Unity Version 2019.2.17f1
Xcode 10.2.1
Swift 4.2
i load unity in a view controller in side my app. loading works fine but when i press back button in unity and Application.Unload(); function is called unity stops and go back my iOS app but after there my app is not responsive. App is not getting crashed. In console there is an error “An abnormal situation has occurred: the PlayerLoop internal function has been called recursively. Please contact Customer Support with a sample project so that we can reproduce the problem and troubleshoot it.”

and one more error “backunity was compiled with optimization - stepping may behave oddly; variables may not be available.” . kindly give a solution for this.

How to stop unity and return back to iOS app and when required i want to start unity again

Did you find the solution? I’m facing this too?