Using WebviewScaffold throws debug error

Using an iPhone X emulator, with WebviewScaffold when it tries to show the keyboard when clicking on a form shown in the webpage. Error does not cause a functional issue but would be good for it not to happen.

Reproduce:
- Using iPhone X emulator
- Use WebviewScafold in a Container widget on a route (similar to example)
- Show a webpage with a form field
- Click form field, bottom webview controls are shown on screen slightly off the screen (next field arrow navigation and Done button), flutter debug window has error

Error thrown:

Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)

....

Will attempt to recover by breaking constraint
=5)-| (active, names: '|':_UIButtonBarButton:0x7faa86552670 )>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in may also be helpful.
flutter: Another exception was thrown: A RenderFlex overflowed by 37 pixels on the bottom.