The Shift + Leftclick selection range appears to break when selecting something in the World Outliner first followed by clicking something in the Viewport and then shift selecting a range back in the Outliner.
Result: The shift selection breaks and ends up selecting a lot more objects than the range of the shift selection.
Expected: The shift selection should just select the 3 cubes.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-63480 in the post.