Atlas passive issues

[Clowknee]

I noticed today during an Eximus sortie I was getting knocked down by bombards when I shouldn't as I was grounded. I took it to the simulator and encountered the same thing. The bombard's nova attack knockdown should be ignored. Instead it causes Atlas to 'surf' the attack, lifting him off his feet but remaining in a walking/running position. It's sort of a stagger but not really. Being an eximus sortie, there were bombard novas chained together. Since I was 'surfing' the first attack, technically Atlas is no longer grounded and would get knocked down by subsequent nova attacks. Is the passive supposed to convert knockdown to a stagger or behave like Rhino's iron skin? Right now it's neither and has an odd result.