Probably the change in culture mostly but I would repot with fresh media if you haven't in a while. You may also find this link useful as it talks about things that turn leaves yellow or make new leaves come in smaller, etc. The website itself is way out of date but this page is still pretty good on adenium problems:

http://www.tropicanursery.com/adenium/problems.htm

Multiflorum leaves are large. They should have remained large as far as I know.

This plant was grown from seed from Rick totally by me. The only difference has been from leds early on, to Sun. However, as i stated, my others still look like multiflorums in the Sun, too. No difference in media, light, or water. They are definitely not short on fertilizer, and the media is fine.

The slightly yellowed leaves aren't the issue, obviously because the newer leaves look perfect, but just don't look like multiflorum.

I've never seen changes this dramatic. I'm stumped.

Hi, Jerry -

Since it's grown from seed under the exact same conditions as the others, perhaps it's just genetics. I have a 3-week old seedling that's doing sort of the same thing. It presented its first set of leaves normally like the rest, then pushed up extremely narrow leaves ...

This seedling is completely different from his "Double Irresistible" sibling, sown on the same date, under the same conditions. In fact, a couple of them look different, just not with these narrow leaves. Very likely just genetics. Omitting lighter green seedling, these five three week olds are from the same pod, "Double Irresistible." Note how different the leaves are on the front center seedling.

- Maria Elena

You are probably right. It's the only thing I believe it could be as well.

Another strange thing about this plant in comparison to its siblings is that this plant is starting to branch at all leaf nodes. The others are not.

Still, I would not have believed the differences could be so large.

I will make note of this plant, and keep everyone updated.

Thank you.