Make a new presentation without template.
Use menu View to switch to Master View.
Select fill type Bitmap in the field Background in the sidebar.
Select one of the images from the drop-down list below that field.
Close Master View.
Add some content, e.g. title and subtitle
Save the presentation.
Reopen the document.
Notice, that the background image is missing.
Open the file styles.xml of the saved file. The <style:style> element of family drawing-page has a draw:fill="bitmap" attribute, but the associated draw:fill-image-name attribute is missing.
Confirmed with 18.104.22.168, 22.214.171.124 and 6.1.01 RC1
Dupe of bug 111306
*** This bug has been marked as a duplicate of bug 111306 ***