Spots associated with leaf holes might be due to Xanthomonas, a bacterial leaf infection similar to the one that causes Cherry Shot Hole Disease on flowering cherries. Usually, though, lesions and reddening caused by bacterial spotting tends to be limited in its spread by major leaf veins, which doesn't appear to be happening here, though it's hard to tell. The fungal pathogen Entomosporium leaf spot creates similar symptoms of red-flushed leaf spots as well, though is most often seen afflicting Photinia shrub foliage, though the fungus does have a wide host range (including many members of the rose family, to which peaches belong).

Some phytotoxicity (tissue damage) from copper exposure can also look like this, so it's hard to determine the exact cause. Did the reddened spots only appear after the copper spray(s)? Routine preventative sprays used for peach cultivation would tend to inhibit infection of the above pathogens, though rainy weather might interrupt that protective barrier long enough to allow some infection to still take place.

For now, just monitor the plant's symptoms to see if they worsen markedly or occur again after another spray application. Weather plays a role in phytotoxicity risk, so in different conditions, the issue might not repeat itself. (Weather also has a strong influence over disease spread and severity.) Feel free to send more photos if the symptoms worsen or change. Meanwhile, any spray plan or regimen you're currently using to protect the tree and its crop from insect pests and diseases should probably continue so there is no gap in protection that might ruin a crop for the year.

Miri