I think this change is wrong: now it would be reasonable to say `{"task": {}}`, which is not what you want; you instead want the `task` attribute at the top level to be optional.  (That is, move from `object 'task', required: true do` to just `object 'task' do.)

You may note that this is, in fact, already the case.  Which might suggest a *different* validation issue existed previously. :)