TextFormField's autofocus from a second MaterialPages is not working.

**Describe the bug**
Once the first textformfield gets focused then the next one from the second MaterialPage is not getting autofocused.

**To Reproduce**
Let's say for example we have 2 MaterialPages:
[
MaterialPage(child: FirstColumnTextField()),
MaterialPage(child: SecondColumnTextField(autofocus: true)),
]
**Expected behavior**
Second textfield gets autofocused as the TextFormField is set. The only fix for now is to set the maintainState to false to the first MaterialPage as follows: MaterialPage(child: FirstColumnTextField(), maintainState: false),.