Is the "protective return veto" unconstitutional?

it is essentially an attempt to pocket veto, knowing that congress 'may' be in session, so the president covers his bases by 1) claiming that he's going to pocket veto the bill, then 2) executes the standard veto by returning it to the house of origin. the executive then claims that they'll view it as a pocket veto (which cannot be overridden). is there any authority or caselaw out there that would bolster the argument that this action is unconstitutional & the entire veto should be ignored?