Tested in 4.14.1, googling around indicates this has been an issue for a long time, did not find another bug report.
If you have an actor with a projectile movement component, whose mesh component is not the root, it will never generate hit events / collide with non-dynamic actors, ergo it will pass straight through world geometry. This is obviously an issue for projectiles that need a collision mesh that is not the root component.
Projectile movement components should not affect whether a a mesh component can generate hit events or not.