Phal compot with yellowing leaves

[zxyqu]

Anyone have any ideas on what this may be, or am I just really unlucky? I haven't watered these since they arrived, so I dont think water has gotten into the crown, but I obviously cant be sure. They are kept at 80+% humidity, and the sphag they are planted in is still wet. The main seedling at the bottom has basically yellowed it's entire leaf, and now a nearby seedling is showing the same signs. A smaller seedling also has a yellowing leaf, but I'm not sure it's related. Would love for some ideas on treatment. Thanks