I think the reason is because update rate is probably 1 frame behind. So when things like this happen, it’s actually better to assign a event dispatcher.( so platform movement and room movement are happen on the same frame)
Work flow is pretty much this, on the platform BP, have a dispatcher, so anything enters the volume will “register” and move with platform when platform starts moving.(with some exceptions, like physics actor, they will moving together if friction is right, or AIs, I don’t think they do well on moving platforms.) And on the Pawn BP, you just have a moveRoom event that are the same signature(inputs) as dispatcher that are new location to snap to. And then you just have to bind/unbind the event when thing move in/out of trigger volume.
I don’t know if matinee is a good choice cause I don’t know how frequent it gets updated, what kind of event it triggers that are usable. Linear movement platform can use timeline for sure, which have a pretty good control to how events are firing.