For your convenience, here is the error:
http://byrden.com/quantum/consistency.html
This paper is wrong.
The error is simple. The overall quantum system is also simple, but obfuscated by the authors spelling out all the steps of the setup.
As some have pointed out here, it's not a system that we could practically implement with people in "labs", no more than we could implement Schrodinger's Cat. But we can implement this system using quantum equipment. In fact Hardy's Paradox refers to a mathematically equivalent system which has been built (and works just as QM predicts).
So it behooves us to identify the error in...
The Renner-Frauchiger paper has been refuted, but usually with a lot of math. So I tried to write the simplest possible explanation, here:
http://byrden.com/quantum/Renner-explained.html