Hi.
for the attached actor, when you attach an actor to another the [Net] Relevancy properties gets override by the “parent” (the actor on top) so be careful about the tick bAlwaysRelevant just in future cases (not related to your current problem)
for checking attachments and updating actor movements unreal like most of other engines. uses DirtyFlag programming pattern for updating transforms in scenes for performance reasons. and that’s why that behavior happens . as you mentioned:
As soon as I move or rotate the parent in any way, the child rotation visually applies.
being honest i don’t know how to invoke the update manually you need to do some googling. let me know my babbling gave you enough search keys to do more farther research. Good luck man!