Leaves growing from roots under the soil?

[Zekeyflower]

Ok, so I have an oncidium orchid that I've had for like a year and a half. I have it potted in orchid bark in a clear pot with slits on the sides. Recently I noticed green leaves emerging from one of the slits (this is underneath the medium). I had to repot it a couple days ago and while checking out the roots it basically just looked like one of the bottom roots was randomly growing new leaves. Is this normal? Is it a keiki? I tried to google this but I couldn't find any info about new growth underneath the medium. Has anyone else experienced anything like this? This is the only orchid I've ever owned and I'm kind of amazed I haven't killed it yet because I don't know what I'm doing. Here are pictures of it- unfortunately it broke off of the root it was attatched to when I repotted it.