IssueTracker

Component used: Navigation
Version used: 1.0.0-alpha01
Devices/Android versions reproduced on: Nexus 5X

Android Studio version used: 3.2 Canary 14
Sample: Navigation Codelab after step 8(adding the Settings fragment).
Added screenrecord showing the issue.

Steps to reproduce:
1) Enter application.
2) From the overflow menu select Settings option. SettingsFragment is added and overflow menu is visible.
3) Again, select the Settings option from the overflow menu.
4) Press back.

Observe that MainFragment and SettingsFragment are overlapping.
This issue does not reproduce when following the same steps using the navigation drawer.

Let me know if this is a Codelabs or a Navigation component issue.

Thanks!