Black patch on Phal leaf. Is this disease?

[lilylove12]

Fairly new to growing orchids. I have a phal that was growing long leaves during the late summer. A few months ago I noticed some dark patches and spots on the leaf which I assumed to be sunburned so I moved it to lower light. (Growing it inside my home near window with shades). About a month ago I noticed a new set of dark patches. I assumed again sunburn so I moved it into even lower light. Today I noticed the patches seem more prominent especially on the bottom of the leaf. Not sure if it was there before but I didn’t see it. They don’t seem to be spreading super fast. However the leaves appear almost translucent. Is this rot or other disease? Should I cut off this portion of the leaf?