In 2020.10.10 for invoke workflowfile activity if one argument value is not passed and the Validation is still not thrown error

I have xaml with 3 arguments,
When i call this xaml using InvokeWorkFlow activity and passed values for only 2 arguments, and for the 3rd no values are passed.

When i try to validate,this is not captured as error.Is it so.
Is this the way it works ,i feel its a bug.

Thanks
Thamaraiselvan.