Oncidium Twinkle -- black spot on pseudobulb?

[GardenGnomeVariety]

Hello!

Need help with figuring out what's wrong with this pseudobulb Other than the black spot on the biggest bulb, the plant seems to be fairly healthy. It's spikes are still developing, roots seem to be fairly healthy, and the other bulbs do not seem to show any kind of stress. I don't believe the browning on the leaves are related (but I could be totally wrong!)

I'm hesitant to do any drastic measures (or anything really) until I figure out what's going on with her. I also can't tell if it's spreading or not but it's been there at least since it started growing its spikes.

Black spot:
https://lh3.googleusercontent.com/zW...B=w397-h705-no

Same plant earlier this year (01/2019)
https://lh3.googleusercontent.com/qf...s=w397-h705-no

Any help would be much appreciated! Thank you!