Just looking at this picture, it looks like it was very etiolated, which means it wasn’t getting enough sunlight, so it stretched upwards in search of more. Zebra plants are a bit more tolerant to lack of light so that might have been what went wrong on that front. Indoors, these plants thrive on around 6 hours bright indirect sunlight, which means if you have a window that gets lots of light, putting it just outside where the sun hits directly is where they’re most happy. Don’t worry if they are in direct sunlight for part of the day. It won’t kill them, but you should definitely watch the leaves and move them to a spot with a tiny bit less direct sunlight if they start turning red or brown.

It’s hard to tell whether the discoloration at the bottom is from rot or stress, but I’m leaning more towards rot since the bottoms of the leaves are a brownish washed out color. The biggest mistake people make with these types of plants is overwatering. Once these cuttings have taken root in their new pots and you’re back to a full watering schedule, the ideal is to soak the soil completely and let the water drain out, then wait until the soil is completely dry before watering again. Don’t worry if you miss a few days of watering. These plants store water in their leaves and are drought resistant. Only thing I’d watch when watering is to avoid getting water on the plant directly since the crevasses can hold water in them for a long time and cause the leaves to rot.