Bulbophyllum stramineum black spots

[LaCucaracha669]

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!