In short: You modified functions list.

Here is the test case in js:

Test.assertEquals(JSON.stringify(chained(fns)(r)), 
                  JSON.stringify(_solChained(fns)(r)),
                  "Random test "+i)

I suggest modify test case to:

Test.assertEquals(JSON.stringify(_solChained(fns)(r)),
                  JSON.stringify(chained(fns)(r)), 
                  "Random test "+i)

With that, we can pop as we wish......

Ah-- you should have marked it as "Suggestion" instead of "Issue". I've added it as a test, anyhow ;P

Indeed. I'm not sure what the issue is you are bringing to my attention?