Hi Rebb,
Apologies for the delay.
As it stands this doesn’t appear to be a bug on my end or from the description above.
If you have a BP that only has a projectile movement component and a static mesh things works correctly, so long as the static mesh itself has collision setup.
By default, the yellow ball used for the first person projectile does not have collision enabled. If you look at the settings in the details panel you’ll see that it’s set to “no collision” for it’s preset. Also open the mesh in the static mesh editor and turn on the collision button in the toolbar. If there is no collision mesh you may need to add it there.
I hope this helps!
Tim