Den. trantuanii - fungal issue?

[NatalieS]

I agree with the above posts - I would just keep an eye on it and see if anything changes.

One of the few orchids to survive my various moves is this particular species (12 years I've dragged it around with me), and in my experience they are prone to leaf spots, which have always been harmless.

Also, I don't know if it's just the lighting or the camera, but the colour green looks a bit darker than usual. These are usually a paler, more silvery/yellowy green, so perhaps the dark patch is from a bit too much light. It's hard to tell, but if the bulb isn't squishy, that would be my guess.