Fill from center for the progress bar in UMG appears to act differently

The progress bar appears to use scaling when filling from the center. However, when moving from side to side or up an down it appears to mask the image in such a way that it hides/ reveals the image depending on the percentage for the progress bar.

1. Open the editor
2. Create a widget blueprint
3. Add a progress bar to the designer tab
4. Assign the attached image to the background and foreground of the progress bar
5. Set the progress bar to fill from center
6. Notice when changing the percentage that it appears to scale the image rather than mask it

Expected: As the fill changes the image will be hidden/ revealed accordingly
Result: The fill image appears to be stretched/ squished