You should really stop just closing all these issues because you think there's nothing wrong with your Kata, especially when they just keep opening up: Your description is very unclear. "The entire pair" to me means the sum of the indexes, but that's not true -- the earlier summand doesn't matter at all, only the later one. So maybe your description should be changed so it clearly states that the chosen choice is the pair with the second index being the lowest. Or, give one "x" and the other "y", or "i" and "j" and say:
Where "i" is the first summand in the matching pair, and "j" is the second summand, the "first" pair is the pair where "j" is the lowest, or occurs first in the list.

I agree with chrisb01 that the kata is somewhat obfuscating. Instructions should be clear, even if solutions are complex. The last element of a pair is not inherently the defining characteristic of the pair as viewed from left to right. If we used the total of the indices of the 2 sets of points as a measure of distance from the left, [5,5] still becomes the solution. When using proximity in a logical application, mathematical rigor should be employed, and thus a discernable pattern emerges.

What it means by the 'entire pair' is that the last element of [3, 7] comes before the last element of [5, 5] parsing from left to right.

Have you seen the whole example block? The last part explains the case you're talking about. In fact, it shows why [5,5] is wrong and [3,7] is right. It's not a kata issue imho.