That doesn't look like mosaic to my eyes but more like a mite or insects but I am also new to roses so I'm just guessing from looking at your pic. Do you know if you see any webs nearby or bugs on the plant during the evening?

Tomorrow would you be able to post another photo from a little further back. I think in this case it might help to see more of the plant. Perhaps there is a bad spot down lower on that cane. Oh and what zone you are from? Do you have winters where you are from?

I tried posting this already but it never showed up so if this is a double forgive me- it's mostly confined to one main cane- one of the older ones coming up from the base. Appeared right after a really awesome spring flush. I don't see damage but with 3 kids and a dog kicking balls all over our yard anything is possible!:)

I don't see any evidence of mites. We do have beetles and rose slugs of course. And I don't spray beyond copper so you'll see a bit of BS.

I agree with seil many of my roses have a little of this or that going on and I'm slowly learning to ignore it.

Well yay! Thanks for the reassurance!