I always thought it was nutrient related. Following to hear the answer too!

I think but I'm not sure it could be a Adenium Somalense. The color of the leaf is right on but some of the pics online show longer and even more slender leaves.

The leaf type can be related to one of a particular species, but w all of the hybridization crossing one species w another. There is no guarantee that you will get all the same leaf form on seedlings of a batch of seeds.

Your first plants leaves are typical of an ‘obesum’s’ and the second plant typical of a ‘crispum’s’ or ‘somalense’s’.

[https://www.houzz.com/discussions/adenium-species-information-dsvw-vd~3667890?n=11[(https://www.houzz.com/discussions/adenium-species-information-dsvw-vd~3667890?n=11)

Here is some info on Adenium Species.

Rick

Thanks Rick!