This looks like a fungal leaf spot infection, but is minor and does not require treatment since they rarely impact long-term plant health. (Fungicides can't cure existing disease -- they can only protect healthy growth from infection, though aren't foolproof and sometimes fail to work well --- and their use may also risk harm to pollinators or other organisms.) In conditions with reduced air circulation (such as from dense, crowded planting or a plant growing close to a house wall or solid fence), or from irrigation that wets foliage, leaf spot infections can flare up since spores more easily infect leaves that don't dry off quickly from rain or dew. As such, plant leaf spot diseases tend to fluctuate in spread and severity from year to year, though removing fallen leaves at the end of the growing season can reduce spore overwintering at the base of the plant, which might lessen infection in the following year.

Miri