I got the same error.

When i typed this in solution area and submit: console.log(result); i got this in output area:"ehT kciuq nworb xof spmuj revo eht yzal .god "
Well the original string should be: "The quick brown fox jumps over the lazy dog.", that mean i do the correct answer,
but still error,confusing... so i have to skipped.

Here's the unhelpful error:

Test Passed

Test Failed: Value is not what was expected

Test.expect(reverseWords('This is an example!') === 'sihT si na !elpmaxe');

This test passes for me, but submitting still give me an unhelpful error...