It looks like perhaps one of the elements may have shifted but you said it's fine on other lenses?
If you're shooting at F1.2, nailing focus might be really tough and since it's so thin it's easy to miss it (I shoot at F1.4 and those times I feel like I have to REALLY take my time to nail them... and even...)

Hopefully you figure it out! Looks like you were shooting a wedding?