Disclaimer: please be aware, I am not a botanist, so there will probably many mistakes here, but I am happy to share any that I know, and delighted to be corrected by others.
Plant tissue consist of several layer, partial mutation that affect pigmentation (chlorophyll or other pigment) on single layer will cause variegation. The tips of plants are the meristem that consist all three layers of cells.
Variegation occurred as results of mutation on gene that control pigments, in two ways
First; mutation at gamete or at seed/embryo, it means all cells are mutant. This can be inherited by seed, but not always since most of times this won’t be the dominant trait.
Second; mutation on tissue levels, on growing plants and only on some cells as a sports. And these are the case of most of variegated plants (a chimaera). If this cells are in the tip of plants/meristem, it can continuously divide along with normal cells, and this will cause variegation. This cannot be inherited but have to be propagated vegetatively from plants tips or branch.
If ones propagates a chimera from a non apical meristem, the baby will came only from single layer of cells, this single cells will then differentiated to other type of cells but still they are just a clone, not a chimera. That’s why you won’t have bi color plants.
Sorry wordy.
I found this site, probably it will give you better ideas than my winding words “NEVER PROPAGATE CHIMERAS BY LEAF CUTTINGS - WHY?”
http://generalhorticulture.tam...
Theoretically if the baby grow from exact border of green and yellow part of leaves, and also consist of two types of cell mixed together, ones can have bi-color babies, but chance are too narrow (I never witness this). This is the case of chimaera spontaneously occurred on grafting (graft-chimaera)
https://en.wikipedia.org/wiki/...