Just wanted to post my experience with this bug " Sphere traces where Start and End locations are the same are not triggering any hits" Unreal Engine Issues and Bug Tracker (UE-68641)
In 4.27.2 using the same start and end location, I do actually get a hit result when the hit is against a static mesh. However, I do not get a hit against a landscape. This had me really stumped until I found this bug submission and realized that the simple workaround is to just add a vector with 1,1,1, to the endpoint. Obviously, this is still a bug, but at least it’s one with a simple workaround.
A more detailed breakdown of my experience can be found here: Why is Sphere trace not returning hit with landscape?