We agree that the symptoms resemble raspberry leaf spot, though it's hard to confirm a diagnosis from the appearance of symptoms alone, since other pathogens or conditions could create similar-looking damage. If these spots are due to that disease, it can overwinter as spores in leaf debris that wasn't removed after being shed in autumn, as well as in canes (stems). Given that, it may be risky to share cuttings with others since canes might be harboring the pathogen, though root cuttings might be okay, as they can send up suckers to propagate a new plant. (Resources we've checked don't mention any infection present below-ground for this disease.)

The more limited air circulation due to the plant's location close to what looks like a solid wall/fence might be encouraging infection, especially if old leaves aren't removed completely from the planting bed after the plant goes dormant. If you irrigate by using a sprinkler or a hose spray, avoid wetting the leaves, since leaf wetness can increase a plant's vulnerability to infection (for most diseases, not just this one). The page linked above includes some management tips to suppress outbreaks.

Miri