Frontal Stun Immunity for Shaman Question

[Killval]

So my question is regarding the Ogre racial of Frontal Stun Immunity, I just want to clarify that I'm aware there are multiple things that can interrupt spell casting such as push, bash, fizzle, channeling skill etc... however, say you are an Ogre and a mob is on top of you, you start casting, the mob bashes from the front, obviously you will not receive the 1-2 second stun that goes along with if a bash hits you, but will you still always be interrupted? I mainly ask because a lot of people have said that the Ogre still can maintain casting even though they get hit via bash? Although every time I have tried this and got hit with bash it still interrupts my cast even though I do not receive the stun itself of course. If this is true, and you get interrupted regardless if you have frontal stun immunity, and just don't get stunned, then I believe this heavily mitigates the usefulness of Frontal Stun Immunity racial, for Shaman of course.