Edit: my first answer was wrong.
What this paper appears to be doing is creating a reversible element which is being treated logically as an irreversable OR. Because the element itself is reversible, it can easily avoid Landauer's principle.
As best as I can tell, this has been known for a long time: you can have a combination circuit of reversible logic, and you only pay the energy cost for the measurements taken at the end of the process (which must latch, so are subject to Landauer's principle).