That looks like damage from mechanical injury, like something bumping into it.

I have to agree with Tiffany. It isn't uncommon for Sans to develop small slits or splits in leaves, but nothing nearly so dramatic as what you have there. How soon after purchase did it start?

If a leaf gets folded or bent horizontally, it will often develop lengthwise splits - the divisions appear between fibers, so they are perpendicular the the way the leaf was bent. Because sans leaves are stiff and tough, they often get handled roughly in stores and nurseries, and the damage doesn't appear until later. I have a very tall Sans that developed some splits from a wind storm. It didn't have to bend all that much, and the splits weren't visible for weeks, but once there, kept getting larger as the plant grew.

The splits don't look great, but the edges heal up quickly and don't really affect the overall health of the plant. Those leaves will keep growing and eventually you will have enough new plants in the pot that you can discard the damages leaves or plants.

How damp or dry do you keep the soil? No one THINKS they're overwatering their plants, but in cool weather, sans rarely need to be watered. My largest hasn't been watered since the summer. Don't let the soil go bone dry, but you should have to dig into it pretty far to feel any dampness. How often you water will depend on the humidity and temperature in your home, and on the water retention of the soil.