Hello,
Sorry, but there was a bug in the Instantiate Object clip when using the optional parent.
I have attached for you here the fixed package.
Also, you would probably want to set the BlendIn parameter to 0 to avoid the popup scale that takes place when BlendIn is higher than 0, since I suppose you want to instantiation to be instant, instead of popping for particles.
Please note, that when not using an optional parent, you can set the instantiation position by using the move gizmo that appears in the scene view when the InstantiateObject clip is selected.
Let me know if things work correctly for you after you import the fixed package.
You are also right. Maybe a dedicated instantiate particle system would make sense. I would take a better look at this option soon.
Thanks.
