Great picture - (Yes, sepals.) i would not worry about THAT at all, and in other instances the plant just shows its colors from time to time; a BIG example to me, and to you ahead of time, is yellow splotches on leaves: don't worry about them, only if, say, more than 4-6 leaves have them randomly and especially if it's a third to a half + of the leaf solid yellow - you know, obviously a problem. Even THEN, IIIIIIIII hit any plant with whatever Miracle-Grow I have at 'outdoor plant' strength and give it a few days. Since I use it ALL the time, i never have had even a minor yellow outbreak;
The ONE time i did? it worked and I've 'never looked back'; You could also 'Search Window' for suspected deficiencies for more-immediate info.
i'd say 'not a problem' here---eg