Den. trantuanii - fungal issue?

[elenfr]

Fresh from my previous plea for help, I am this time asking about a recently bought Dendrobium trantuanii.

It was described as "not blooming size", which looks to be an understatement (the pot is 6cm)! I understand that such small seedlings are particularly sensitive to any issues with their culture. With that in mind...

As you can see, the leaves are spotted (they were like this on arrival). Might this be a fungal issue? If so, how should this be treated? For what it's worth, they are growing at ~50-60% humidity.

More concerning to my untrained eye is the dark colouring on (or in?) the larger pseudobulb. What are your thoughts?

Any guidance much appreciated.