W2 lifter problem

That's a fast cam lobe. Just my opinion here, but if there was a mechanical interference issue, I'd expect to see it on all lifters, or at least all intake lifters due to the offset. I know hydraulic rollers that are much taller will have issues like that, but I'm pretty sure the 5/16 half ends are fine on them. However the radius of the lifter cup may not be for a 5/16... Are the 6 a mix of intake and exh?