Good question here.
It is not considered universally legitimate and may in fact just be a stylistic trait of the person you mentioned, as it is (to my knowledge) not commonly done or practiced.
In 12-tone music, it has been jokingly said that "everyone cheats" and that is more or less true - composers often break away from the rigid structure and follow their ears / intuition in order to realize their artistic goals. It is rare that someone follows every single rule of 12-tone composition perfectly and ends up with something profound or meaningful.
I'm going to refer to the Second Viennese School here for examples of different approaches to 12-tone technique.
Of the three composers most closely associated with the Second Viennese School (Arnold Schoenberg, Anton Webern, and Alban Berg,) Berg was the loosest with his treatment of rules - he would sometimes skip notes of rows or go back a couple of notes and repeat them. Sometimes his rows were incomplete or sometimes he would have gratuitous chromaticism. By contrast, Webern was one of the most strict - with pitches almost never (if at all) ever being repeated.
Other composers such as Stravinsky and Copland further employed their own personal takes on the rules as well.
Generally speaking, in the strictest 12-tone theory each pitch should only be played once and only once, the exception is the repetition of a current pitch such as "C#-G-Ab-Ab-Ab-E" would be acceptable.
Like most things in their respective subjects, it's okay to break the rules if you know the rules and you understand / have reasons for why you are breaking them.
Hope this helps!