You haven't enabled "Can Pool Same Object Twice" in your Multiple Object Pooler script, that might be the cause of the problem.
An Asset is anything you can get from the Unity AssetStore (just like PlayMaker), so unitypackages that contain sounds, sprites, or whatever the asset creator contributes (you for example seem to use the Corgi Engine Asset).
I asked because it narrows down the sources of possible problems related to yours (if it would have been an own implementation, the problem was likely to be somewhere in there).