Q.Looks like 2 trees in one seed.
I have a avocado seed in water. It has grown a stem and is about 2 inches tall now with leaf buds starting to spread. I just notice that there appears to be another stem starting in the split of the seed, it hasn’t come out at the top yet. It looks like another tree. Is this possible? There is only one large Tap root and 2 other little roots starting.

Certified GKH Gardening Expert
All the images I saw only showed one stem, but two? Why not? You might have an anomaly or mutation. Good luck!
https://www.gardeningknowhow.com/edible/fruits/avocado/indoor-avocado-plant-care.htm