Bulbophyllum stramineum black spots
 

Hello everyone,
I just bought one week ago this orchid beside another Bulbophyllum(Rotchildinum)
When i woke up this morning I could noticed these black spots on its leaves, and one of its leaves turned yellow.
What can it be?
I must say that its grower divided it a day or two before he gave it to me(Can it be trauma?).
The weather is around 21c and i provide my orchids around 70% humidity till night.
The other orchid which got divided as well was the Rotchildinum which is totally fine, his leaves are green and it looks nice.
What could have gone wrong with the Stramineum?
Thank you!

Division could cut roots and get infected. Rotchildinum are very strong but when you dived it some bulls could die.

If it was mine I would apply a little fungicide; ecological or store ready.it looks infected to me.

The bulbophyllum in the pictures is the Stramineum not the Rotchildinum.
The Rotchildinum is green and healthy unlike the Stramineum that you see in the picture. Any reason why?

The whole thing just looks a bit weak. The black spot is just part of that diagnosis.
From what I can see most the roots are not functional. I can see one root that looks ok but that needs to be watered more regularly.
It's going to need plenty of watering and dying out if this one has a chance,

As I said, for me it looks infected, some virus. I'll tread it and as @Shade said, constant watering.

I don't let Bulb dry though, I have them wet/humid 24/7.

I don't think virus, fungal or bacterial issue more likely. Probably trauma from divisio So fungicide would be a good idea. Also, this is a rather warm growing species, so if you can keep it a little warmer that might help. Bulbos do like moisture, so you will have to balance between "wet enough" and not encouraging fungus. Humidity seems good, you don't want to go higher, but keep medium damp.

I woke up this morning and the situation did not look good.
I cut out the infected leaves, and sprinkled cinnamon on the plant and where I cut.
I fertilized and watered the plant and now I let it recover with the hope that it will survive under artificial light.
I also tried to use Quaternary Ammonium Compound in order to help the orchid.
Do you think he has a chance to survive like this? How many hours under the led will he need during the day?
I would love tips in an attempt to save the plant.

I very rarely throw something onto the compost but that has had it.
Ammonium is not very safe for orchids, doubt that will have done it any good. The fertilizer yes, the light yes but it's all a bit too late.
Best rememdy is to provide the right care in the first place, not use those requirments to rectify when it has gone wrong.
I think low temps and too much humidity will have been the main factor here.

I wouldn't be thinking where did the fungus come from - fungus lives in the air all around us all the time. Plants are strong enough to not get attacked but once they weaken the fungus takes hold. So you should be thinking what did I not provide this one (light, temps, transport shock, repot stress, lack of fertilizer) that weakened it

Is it possible to contact the person you bought it from? The fourth picture in your original post looks like something 'not so good' is going on with all of the leaves. Was it like that when you first received this plant?

I agree with Roberta's thoughts & suggestions about your situation. Temperature and humidity levels (that you mentioned) seem acceptable. Never say never, but I don't think all of those leaf spots, showing up within a week's time, were a result from your end.

You can only hope for the best with it's recovery, albeit it will be a very slow recovery if it does survive. Shadeflower's words also come into play now. Seems like there have been so many name changes in recent years, I'm still not quite sure if the accepted name of Bulbophyllum stramineum has been officially changed to B. cumingii... almost a full time job keeping up with the name games.

It might have been too cold in shipping.