multiple correct answers in DV poison reverse exercise

[leonardomaccari]

In the exercise at the end of the Distance Vector section (https://github.com/cnp3/ebook/blob/master/principles/dv.rst) there are multiple correct answers, but only one is accepted.
Router R0 may reach R2 via R1 or R3 as the path length is the same (2). This does not affect the exercise without poison reverse, but with poison reverse the DV sent to R1 and R3 changes based on the choice made. Once the student chooses one of the two options she can consistently input the correct answer, but in one case the answer is marked as wrong.

In the attachment it seems that the path R0-R3-R2 is considered wrong