Is that a fused flower? Draw a line down the middle, the two sides of the bloom look like mirror images of each other. Sometimes the reproductive parts have an abnormal number. The other clue is that the center is wider that it should be, as if it was two centers, side by side. Normally a fused flower is only in one bud, but I think that your other buds look as if they might also produce fused flowers. Very interesting. I think you might have a Minerva that has, for some reason, produced fused blooms or has some other structural abnormality. Next year, it might continue doing "its thing" or it might revert to a normal form.
This is my photo of Louise with a fused flower to show you what I am talking about.