Do you use anything like roundup? Have heard that causes streaking sometimes.
Margo (reed) has one that shows variegation sometimes. I think it is Rocky Horror. She sent it to me in variegation but it has not shown it since.
However, it is in her line somewhere else, I one of mine, AHA! had variegation when I divided it out. I'll try to find the pic. The plant stayed variegated so far for two years. Replanted this past fall so not sure if that will affect it for this year. They are puny as compared to the other divisions around them.
Here it is showing first year variegation. It is out of Creature of the Night and Skinwalker. C of N is Margo's.
I would love it if daylilies could have variegated foliage AND a pretty plant AND flower!