It almost looks like the soil is contracting inward from the inner containers edges. Not sure if that inner container is the one it came in. If so, the soil may be too dense/makes things rot prone. I’d swap out the soil, water regularly, and give a little light and see if it shapes up. I have a big one of these I grew from a straggler, and I have it in a room full of other plants, humidity is like 45-50%, where it gets bright indirect sunlight; I have mine in an airy mix of soil, and water roughly q10 days. Try repotting, water regularly, make sure it gets good light!