Was there a recent undocumented change to how Popup's HorizontalOffset & VerticalOffset work?

[kmgallahan]

Per the title, I recently noticed that I'm either mistaken or these no longer work as documented:

Gets or sets the distance between the left side of the application window and the left side of the popup.
Gets or sets the distance between the top of the application window and the top of the popup.

They now appear to be an offset from the Popup's parent UIElement.

@gegao18 You look to have recently worked on a semi-related issue: #9433