It could be just the natural ageing of the leaves. It may mean a lack of water or check the leaves for blackspot. Even a rose that has been nearly defoliated by blackspot may be reinvigorated by summer pruning back to 18 inches or so. Remove and destroy all the affected leaves. Do not put them in the compost pile.
Sense of smell varies from person to person just as the sense of taste varies.
Some varieties provide a fragrance that everyone may smell and others may be more subjective. The beautiful, deep pink, climber Viking Queen produced a fragrance that John and two others found outstanding. One of the staff and I could smell nothing. I know a rose breeder who says he can never smell any fragrance on a yellow rose. If your rose doesn t rebloom it could be a once blooming variety.