Also having this issue but for me it still exists and not just a visual bug.
On reloading UEFN my prop manipulators have turned from points into boxes even without the box ticked. Ticking and unticking seems to help until next reload. Problem became noticable as some of my props are close enough to be covered by the bugged block volume of nearby manipulators.
Luckily most of the manipulators in my scene dont require a volume.