On the subject of variegated Aeoniums, here's a couple of related plants to compare, by way of example. They are not your plant but they do tell a story.
The first plant (Sunburst) is marginally variegated, the second plant (Starburst) is more subtly variegated on the center line of the leaf instead.
The interesting part is that Sunburst was the parent of Starburst (presumably a reversion or mutation) so they are quite similar in terms of size, flowers, etc. These are the sorts of changes you see in some variegated plants, given enough time and numbers.