This nirvana papaya appears to be a rnt or something, Its grown very slow compared to the others. MOst noticable is the fact that the stem is very soft and flimsy. IN addition, its got a reddish color to it. NOw, ive used the same foxfarm products for the others who are gorwing 5 times as fast, so I dont know how this could be a deficency. IN addition lower leaves have a little rust spots but theres 4-5 nodes of leaves that look great
Who knows, something might be different with the conditions in the soil or something. How old are these plants, how tall, when and how much have you been feeding them, what kind of lights and soil, etc? Check the ph as well and check for root rot caused by over watering or too much humidity or both.