Yellowing Patches on Leaf

[Vpplaya]

Hello everyone, I was wondering if anyone could help me identify this yellowing one of my phal leaves is experiencing. This is my first orchid, and it has been very healthy up until now. The flowers have fallen and the spike is turning brown so I am getting ready to cut it off and re-pot. Yesterday I noticed that one of the big leaves has these yellow splotches forming on it, yet no other leaves do.

I have also noticed tiny clear insects in the soil but I believe that they are just springtails. Not too worried because I will be changing soil soon. I thought that it was a nutrient deficiency so I fertilized it but now I am not so sure. Any feedback would be extremely helpful, thank you.