Hi hardballs,
Ah that makes sense! The reason it doesn’t get attached is because the projectile movement component acts as a component on the entire blueprint as opposed to an individual portion and cannot be parented to another component. If the component was not added to the child and instead was in the parent and the other parent did not have a projectile movement component or different specs within their projectile component, it will alter the child accordingly as it is losing access to those components until told otherwise (i.e: adding the component to the new parent or directly to the child blueprint).