Need some expert advice

Hello All,

I need some advice from you experts out there. I have a blueberry headband fem. that has a yellowing leaf. Two days ago I transplanted from the original seeding containers to fabric 3 gallon pots, fox farm soil is the medium. I watered this morning and began my first attempt at low stress training after putting the plant back in the tent I noticed the yellow on one leaf. I am not sure if this is a deficiency it is only on the one leaf of the one plant.

Suggestions Welcome!