About a month ago, I bought a few lithops from someone online through a Facebook group. One of them came a little squishy and wrinkled looking, but I assumed it was from being in a dark box for a week. I took them out and adjusted them to full sunlight over a week, then planted them in a pot with a very dry, gritty soil mix. At the time I received the plants, the seller had told me they had been watered around 2 weeks prior, and that they were due for another watering. But I thought it would be better to withhold the water than to risk overwatering, so I haven't watered them at all since then.
That one particular plant keeps getting more squishy and wrinkly, and has shrunken a bit. Was it overwatered? I thought when lithops are overwatered they swell... There doesn't seem to be any damage, and when I planted it, the roots looked fine. I thought it might be producing a new set of leaves, but it doesn't seem to be splitting apart, and when I squish it a little, it almost feels like jelly inside.
They are in my shed in a south-facing window, which I leave open all the time. It's probably not the weather. I live in northern California, it doesn't get too hot or too cold here.
The photos I've attached were taken about 3 weeks apart.
Any advice is appreciated... Thanks in advance!