Windows Phone 8.1 BottomAppBar disappeared after resuming or navigating to another page

Question

I have BottomAppBar declared in xaml for one ListPage and another BottomAppBar in ReportsPage. Sometimes when app resuming BottomAppBar disappeared and it's often disappeared when i'm navigating from ListPage to ReportsPage using MessageDialog control.

ListPage:

<Page.BottomAppBar>
    <CommandBar x:Name="bottomApplicationBar" Loaded="FrameworkElement_OnLoaded">
        <AppBarButton x:Name="AddAppBarButton" IsEnabled="True" Label="{Binding [select_button], Source={StaticResource LocalizedStrings}}" Icon="Edit" />
        <AppBarButton x:Name="RefreshAppBarButton" IsEnabled="True" Label="{Binding [refresh_button],Source={StaticResource LocalizedStrings}}" Icon="Refresh" />
        <AppBarButton IsEnabled="False" x:Name="SetTripTypeBarButton" Label="{Binding [triplist_bulkedit_set_trip_class], Source={StaticResource LocalizedStrings}}" Visibility="Collapsed"  Flyout="{StaticResource TripTypeFlyout}">
            <AppBarButton.Icon>
                <FontIcon Glyph="T" FontWeight="Bold"/>
            </AppBarButton.Icon>
        </AppBarButton>
        <AppBarButton IsEnabled="False" x:Name="SetTripPurposeBarButton" Label="{Binding [triplist_bulkedit_set_purpose], Source={StaticResource LocalizedStrings}}" Visibility="Collapsed" >
            <AppBarButton.Icon>
                <FontIcon Glyph="P" FontWeight="Bold"/>
            </AppBarButton.Icon>
        </AppBarButton>
        <AppBarButton IsEnabled="False" x:Name="DeleteAppBarItem" Label="{Binding [triplist_bulkedit_delete], Source={StaticResource LocalizedStrings}}" Icon="Delete" ></AppBarButton>
        <CommandBar.SecondaryCommands>
            <AppBarButton Visibility="Collapsed" x:Name="allTripsButton"  Label="{Binding [triplist_bulkedit_all_trips],Source={StaticResource LocalizedStrings}}" Icon="Font" />                
            <AppBarButton Visibility="Collapsed" x:Name="allTripsPurposeButton" Label="{Binding [triplist_bulkedit_missing_purpose], Source={StaticResource LocalizedStrings}}" />
            <AppBarButton Visibility="Collapsed" x:Name="allTripsFromReportButton" Label="{Binding [triplist_bulkedit_all_trips],Source={StaticResource LocalizedStrings}}"   />
        </CommandBar.SecondaryCommands>
    </CommandBar>
</Page.BottomAppBar>     

ReportsPage:

<Page.BottomAppBar>
    <CommandBar x:Name="submitAppBar" IsOpen="True" >
        <CommandBar.PrimaryCommands>               
            <AppBarButton x:Name="submitReportAppBarButton" Label="{Binding [report_submission_submit_button], Source={StaticResource LocalizedStrings}}" Click="SubmitReportAppBarButton_OnClick" Icon="Accept" IsEnabled="False" />
        </CommandBar.PrimaryCommands>
    </CommandBar>
</Page.BottomAppBar>