Apparently those strong guys want to spread out. Give them lots of room, or they will muscle their way out.
I've got to look into growing more Sans varieties and getting to know them better. So far, I only have the common ones. I had Moonshine once, but gave it away when I had to downsize because of illness.That's one plant I should have kept as it was nearly carefree. I'm still kicking myself for getting rid of it, as the person I gave it to, didn't take care of it.