Hi,
I’m afraid, that the .ass format isn’t fully supported. Because of technical limitations, it’s not showing correctly in the viewport – by using the moment using the Proxy Viewport mode you should at least see the “center” of these items when used within the Forest object(s). On the other hand, these items should render just fine – in case of any troubles, please double-check the “Pivot Point” position of the used object(s).
I hope that helps a bit.
Best regards,