You have four photons - A, B, C, D. A starts off entangled with B, C starts off entangled with D.
What the experiment appears to show is that if B is then entangled with C, then A is effectively entangled with D. In other words, entanglement is transitive. What it does NOT show is a violation of causality,
What the experiment claims to show is that if A and D are measured, then B and C are subsequently entangled, then A and D were effectively entangled at the time of their measurement.
Had there been an indictment, we would be having a different discussion....
If mathematically you end up with the wrong answer, try multiplying by the page number.