Here is one of my tagged fish caught and showing the red sores...
I can see one issue with this tag. looks like a clothes tag and the "FAT" part of it was left on the snag in the FA causing drag and irritation. If you clipped it off so it was just a straight slim tag it would not get caught up in the FA and cause drag on the tag and fish as it swims. Seems like that would help any way.