Looks like a new growth...so it will become a new pseudobulb, topped with leaves, just like the others. So, a good thing. Catts will put up a new growth, and then as the growth matures (and if the plant is old enough and feels like blooming), that growth will put up a bloom sheath. They only bloom on new pbulbs, not on old ones (but old ones help provide energy for the plant, so they still serve a purpose.) It looks like your plant is happy.