Well, the way it's written, it kind of is... :)

Not the easiest code to read at all.

This Kata was never approved, because FArecashew filed an issue that was basically an opinion which therefore couldn't be resolved.
I humbly disagree with FUkissU so I marked his 'issue' resolved, clearing it for approval. Which I will do after I finished this comment.
With an average satisfactory rating of 88% this is good enough.

Interesting. Thanks for the insight.

There's no good standard for this. Some kata never leave beta because they have lingering issues authors do not want to fix. Some manage to collect enough negative feedback that they cannot get to approval requirement, but not enough to get retired. Difficult kata or kata in unpopular languages can stay a year or so before they get enough solutions.
Relatively easy kata with not many issues and authors actively fixing them can get out of beta in a matter of days, often accompanied by a bunch of translations.

"&&" is preferred over "and" as a logical operator in Ruby, "and" can lead to unexpected behavior in some cases.

Here's an answer I wrote up on Quora about it: Why don't many programmers use the keywords "or" and "and" in their programs but always opt for "||" and “&&"?.

Out of curiosity, how long do new kata typically stay in Beta? Is more than a year pretty standard?

This is by far the hardest 6kyu I've completed. Most 5's and even some 4's that I've solved are easier. Is there any consideration for regrading this Kata?

Agreed. I was even thinking a 4, most 5's are easier than this one.

It says to sort them in alphabetical order in the case of ties.

In the ruby version, the closing parenthesis is in the wrong place in the tests, giving a "wrong number of arguments" error by default

It should look like this: Test.assert_equals(elements_sum([[3, 2, 1, 0], [4, 6, 5, 3, 2], [9, 8, 7, 4]], 16))

But instead, the tests look like this: Test.assert_equals(elements_sum([[3, 2, 1, 0], [4, 6, 5, 3, 2], [9, 8, 7, 4]]), 16), so the 'd' value is never passed in as an argument.

Is this the only recursive solution?