Oncidium twinkle leaves with spotting

[sweta]

The same oncidium twinkle orchid regarding which I posted about browning leaf tips earlier last week is now having some other issues. Some leaves have tiny black spots and one of the leaves has tiny scabs and another one has brown line along the middle of the leaf. I'm attaching the pictures. Could this be scale? I'm dealing with scale issues on some of my other orchids that are currently quarantined so I'm so paranoid as I have other seedlings that I dont want them to get infected.
This seedling is grown in bark and sphagnum moss, watered once a week, fertilized once every 2 weeks. Temperatures at home is 70F and dry. Please suggest what can I do if this is indeed scale and if its not ,could it be some fungal infection?
I spot treated the leaves with some horticultural oil but not sure if that will be sufficient if its indeed scale.