That is a pleasant surprise! And an especially pretty leaf.
What gets me mesmerized is the grayish section that can appear between the yellow and the dark green. That seems to be what is so unusual about this plants' variegation.
I'm not sure symmetry is a thing for this cultivar. From what I've seen, the fact that there is variegation is stable compared to a lot of variegation, but I don't think I've seen 2 identical leaves in the years I've had that one. The yellow part can be a thin stripe, or most of the leaf, in the middle, or off to one side. I did get a solid lemon/lime color stem a few years back, but it didn't survive on its own after I cut it off. That was the only abnormality I've seen on my own plants, for asmuchas the variegation of this cultivar can be called normal.
Don't tell me you haven't already thought about prop'ing it.
