I have one that does that also. I really don't think it's rotting - just a way to ditch the backbulb. But since you just received it and you expected something more green, I would try to get a replacement. Just don't be surprized if that one does the same thing in the future.
Hello Memder and welcome to the OB, while I don't currently grow the genus you got there I would ask for an exchange based on the sole fact that you didn't pay for a sick orchid so why would you keep this one?, As for the bulb... kind of out of my league, I grow phals mostly
Sorry to have this happen to your first orchid, don't let this discourage you
Hi Memder!
I just looked closely at mine and I do not have spots on the leaves. (Some types do, so went to check, but not Jerry's Pick). I think misting causes spots like that, so perhaps water got on it at the nursery causing that. I don't think that is anything to worry about. However, that area doesn't look good on your pbulb. Where did you get this plant? It does look a little scary and if it were me, I would definitely ask for an exchange. I see it's in moss, too. Hmmm. It's iffy at best. I am not an expert but I don't like that blemish...that looks like rot.
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I have heard good things about Logees, so they should replace it no problem.
The orchid you have is a gorgeous one and I think you'll be pleased with it once you get this straightened around.
Good luck and keep us posted.