I don't know if this is a rebloomer that hasn't hit its stride in your zone? Or what. Depends upon how much you liked the bloom. It looks very healthy.

Thank you, Iris-gal.

Sometimes if you get really cold temps after the iris start to grow, I mean temps like 18 degrees F or so, the foliage and especially the bloomstalks will get weird in various ways. What you have looks like some of that kind of damage. Some varieties are more prone to this than others.