Leaves turning yellow

[Hugorchids]

I have a sanderianum hybrid and noticed some of the leaves turning yellow and translucent. I thought it was due to some high heat damage and had since moved the plant into a cooler/shadier spot. It has since continued to turn yellow and I decided to cut them off. Is this a bacterial/fungal issue? Snapped some pictures tonight, hope someone can give some insight.

 

[Linus_Cello]

When did you last repot?

 

[Hugorchids]

Good question! I didn't see a date on the tag so it must been at least 3 years. I planned to repot as soon as the blooms are done.

 

[Ozpaph]

that look ominous! Check the roots and remove anything dead or dying.