Plugin's Target missing attributes

Hello,

I have an entity called Student with two attributes - an OptionSet field called Status and a Lookup field called Faculty.

On a record update (Post-Op) I'd like to trigger a plug-in whenever the Status changes to a certain value.

The record to be updated has a Faculty attached to it already.

My code is as follows - 

        Entity studentTarget = context.InputParameters["Target"] as Entity;
            new_student student = studentTarget.ToEntity<new_student>();
            if (student.Contains("new_faculty") && student.new_Faculty != null && student.new_Status.Value == 3)
            {
              // some logic
            }

But the Faculty attribute returns null. 

P.S. When registering a new step to the plug-in , in Filtering Attributes, I included both Faculty and Status attributes.

What could be the problem here?

Is it because the Faculty doesn't change that the attribute returns null? If so, how can I resolve this problem?

Thank you