you can throw break while backdashing to be in a non CH state, but some characters get huge damage on air confirms (mitsuru, narukami come to mind)
if you mean whiff a grab and have izanagi attack, yeah that happens when you try to grab while izanagi is out after 5d. if they jump/backdash the persona attack will come out, hopefully letting you keep pressure. 5dd is not that quick however, and if they do a move thats fast enough they can break the persona and still cancel into something else to hit you.