UnloadAssetBundle failed

I got error when i unloaded an AssetBundle with AssetBundle.Unload(true) function.
error description:

1:
m_PreventLoadingFromFile != nameSpaceID
UnityEngine.AssetBundle:Unload(Boolean)
IceCream.DialogController:OnDestroy() (at Assets/Scripts/IceCreamScene/Dialog/DialogController.cs:81)

2:
UnloadAssetBundle failed
UnityEngine.AssetBundle:Unload(Boolean)
IceCream.DialogController:OnDestroy() (at Assets/Scripts/IceCreamScene/Dialog/DialogController.cs:81)

i just created this assetbundle from file, then load and Instantiate a prefab from it.
but i failed to unload it.
i found i load and instantiate other prefab will not met this problem, but the prefab described below

60619-unity-assetbundle-unload-fail.png

PlayerCamera and PetCamera both are render their content to RenderTexture.
Player is a normal model.

Thanks…

i got similar problem。
i make a prefab, it have a camera, the camera is used to generate render texture.
i build the prefab into assetbundle.
when i unload the assetbundle (assetbundle.unload(true)),
editor log the error like this, m_PreventLoadingFromFile != nameSpaceID .
but editor didn’t crash