I was just out looking at some of mine and they look just that bad. I am watering them more now and I think next year they will be fine. Just too much sun here at this time of year, even though they are mostly under big oak trees, some spots just let the sun slip though. Not sure about it being Sagae.
The last two along with some that are not sunburned are growing in this bed.The afternoon sun is hitting them just right to fry them.