Update to partial fizzle
The part of the "fizzling" rules that your question is about haven't changed recently. The rule quoted in the page you linked to, 608.2b, says in part


  If all its targets, for every instance of the word "target," are now illegal, the spell or ability doesn't resolve.


In the example you gave, one of the targets is still legal, so the spell still resolves.

The part of the rule that changed recently is that it used to say that the spell would be "countered", but now it says that the spell "doesn't resolve".