Check for any kind of infestation, RTH. Sometimes, pests take up residence on one plant and ignore others. I'd spray it with horticultural oil all over and under the leaves, as well as the surface of the soil and all over the pot. The best time to do this is after sundown so it dries overnight before it is exposed to the sun again. If the leaves are otherwise healthy, that will hopefully fix it.

Also, the variations in adenium cultivars are sometimes so weird that even if they are the same species, one plant may need more water than another. I have seen this more commonly among grafted plants.

I hope it gets sorted out.

Pagan

Good thought! This is a grafted plant and because i have it in a larger pot I've used a lighter faster draining mix. Maybe not enough moisture... Will spray in case of some infestation. I thought I might have seen borer holes in a couple of buds early on but haven'tnoticed any since so thought I'd been seeing things. I'll spray tomorrow evening. Thanks.