Oxyclean blue stains?

I soaked a load of filthy camp clothes in a laundry tub with oxyclean as a prewash. A white shirt now has sporadic blue/grey streaks at several different locations that I can't remove. I think it is some kind of staining from the oxyclean blue agent. I thought the poweder was dissolved, but maybe not. I don't think it is bleed from other clothes because I have had other clothes ruined in the past following an oxyclean soak (pink shirt with blue grey stain and a yellow sweater with blue/grey stain -- two separate occasions). I can't tell if the discoloration is a stain on top of the fabric color or if the stain is a removal of original dye.

Does anyone know how to get rid of the stain? I washed in laundry twice - once with bleach, and soaked in clean water. I was trying to fix this before the shirt went in the dryer, but my husband didn't know my plans and the shirt eventually went in the dryer. I don't know if placing in the sun with lemon juice will help. I read a suggestion to soak in vinegar, but I have used vinegar to set color so I don't trust using it to remove a stain.

All suggestions appreciated!