Oh yes, Hoya kerri variegata is really reticent to form leaves. My plant just makes one or 2 leaves each year, its leaves and vine really thicker and less flexible compared to other hoyas. Have not dared to root a part of it, too afraid it just might not make it, being so reticent as it is, don't want to waste the precious vine and stem.
Saecho, give your plants some time. Plants are beginning to adjust their growing mode now that it is Fall, whether your grow them indoors or outdoors. Sunlight is getting shorter and temps going cooler. I hope your plant recovers.
Hoyas are tropical plants so it will pout first before it adjusts.
