Can't use cast in ABP_Mannequin_base Thread Safe Update Functions

In Blueprint Thread Safe Update Function, use cast to xxx will cause this error , if do this in ABP_ItemAnimLayers is ok, why?

[Compiler] The type of Object is undetermined. Connect something to Cast To Bxxxxxx to imply a specific type.
[Compiler] The current value of the ’ Object ’ pin is invalid: Unsupported type Wildcard on pin Object