u/Solid-Let6560

I have some absolutely BEAUTIFUL blooms on my desert roses. However, the last 2 days I've noticed alot of yellowing leaves which fall off. Am I over watering? Not watering enough? I just need some help and advice. My plants seen to be thriving but this yellow falling leaves can't be good right? I'm a newbie with desert roses but absolutely LOVE them!! Any help or advice is greatly appreciated. Thanks!!