Microsoft-ui-xaml: DatePickerFlyout: Selected date does not receive updates from source.

Describe the bug
A DatePickerFlyout whose Date is two-way bound will update target-to-source but not source-to-target.
The following link refers to the same bug and provides a simple (outdated) example project: https://social.msdn.microsoft.com/Forums/windowsapps/en-US/240718c8-a5ee-4528-a748-0d6511401dcf

Steps to reproduce the bug

1. Create a button with a DatePickerFlyout as an AttachedFlyout.
2. Create a second button that sets the DatePickerFlyout.Date to today.
3. Change the date inside the flyout.
4. Hit the reset button.
5. Open flyout; The visible date is still what you have selected in step 3. The DatePickerFlyout.Date is exposing the correct date.

Expected behavior
Visible date should reset like it does with DatePicker or TimePickerFlyout.

Screenshots
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Version Info
Microsoft.UI.Xaml 2.0.181018003.1

Windows 10 version:

• [x] October 2018 Update (17763)
• [x] April 2018 Update (17134)
• [x] Fall Creators Update (16299)
• [x] Creators Update (15063)
• [x] Anniversary Update (14393)

Device form factor:

• [x] Desktop