Thank you for your post.
This means your have an object "Anchored" at the bottom (probably one of the buttons in your footer). You would want to check anchors on those objects and, if you don't want the layout extended, have only anchors on the top and left.
I hope this helps!
The second layout is in List view. In list view the footer is always at the bottom of the screen (and the header at the top).
Try changing the part to a trailing grand summary.