1.
Material doesn't have a texture property '_Metallic'
UnityEngine.Material:GetTexture(String)
MaterialTree:ApplyOutline(GameObject, Material) (at Assets/Scripts/InteractController.cs:184)
MaterialTree:ApplyOutline(GameObject, Material) (at Assets/Scripts/InteractController.cs:191)
InteractController:Select() (at Assets/Scripts/InteractController.cs:118)
InteractController:Update() (at Assets/Scripts/InteractController.cs:63)

2.
Property (_Metallic) already exists. Use SetTexture instead.
UnityEngine.Material:SetTexture(String, Texture)
MaterialTree:ApplyOutline(GameObject, Material) (at Assets/Scripts/InteractController.cs:184)
MaterialTree:ApplyOutline(GameObject, Material) (at Assets/Scripts/InteractController.cs:191)
InteractController:Select() (at Assets/Scripts/InteractController.cs:118)
InteractController:Update() (at Assets/Scripts/InteractController.cs:63)