The truth of the statement does not derive from being an inverse, converse, or contrapositive of the statement before it. Rather, it is inferred from what we defined "NPR" to mean.
Since "NPR" is defined as true if what follows it is never printed twice in succession, and "NPRNPR" is never printed as a given, then "NPRNPR" as a statement is true.
Since "NPR" is defined as true if what follows it is never printed twice in succession, and "NPRNPR" is never printed as a given, then "NPRNPR" as a statement is true.