Component used: Navigation

Version used: 2.6.0-alpha05

After upgrading to Navigation 2.6.0-alpha05, swapping to another tab via a bottom bar set up via NavigationUI works the first time, but pressing the back button doesn't work as intended: while the fragment changes, the selected bottom bar item doesn't change.

Sample project: https://github.com/muzei/muzei

Steps to reproduce:

Run Muzei, tap 'Activate' and then 'Set wallpaper' to set Muzei as your wallpaper.
Tap the Muzei icon to complete the tutorial.
Tap the 'Sources' tab on the bottom. Note the tab changes.
Press the system back button.

Expected behavior: you go back to the 'Muzei' fragment and the selected tab updates.

Actual behavior: you go back to the 'Muzei' fragment, but the selected tab does not update.