Black/Yellow Spots on Oncidium Leaves

[butterfly_muse]

Afternoon, all! Long time no speak. My orchids have been happy and well.

I recently purchased on Oncidium Twinkle Pink Profusion online and today it arrived. I am concerned about some black/yellow spots, and some yellowing I see on its leaves. I am wondering if it's something I can treat, or if I need to send it back?

I have attached pictures. I figured from some research that the black/yellow spots are probably some sort of fungi, which I've read can be pretty common with some oncidium types. What I'm not sure about is the bright yellow you see on the one leaf in particular. I'm not sure if that's a virus or what that is. I also think he's a wee bit overpotted, if he's anything like the oncidium I've got downstairs (which is gigantic and loves being squeezed into its pot. It currently has 12 flowers on it, so I'm sure it's happy).

In the mean time, this little guy is quarantined from everyone else. I'd like to get him sorted out if I can, as he's a nice looking little plant otherwise.

Thanks in advance for any help!