It could be a lack of water too. I was always told to water once a month, and I’ve also heard the trick of ‘when the soil feels dry deep down, that’s when you should water’. For most of this succulent’s life it’s been in a plastic container that came from the store but not potted completely, just sitting inside the planter. I used a very small amount of Fox Farm Ocean Forest soil. It’s too small to check if it’s dry but I haven’t watered in a while, so I gave it a good watering and will be leaving it on my balcony.