@sooby, many thanks for your interest.
I'm attaching a pic for an overall look so maybe you can get the answer you asked.
The DL at the bottom of the pic is fine, new foliage (it went dormant for short).
The second going up is one of the "affected" DLs. It's Taffetà Mist (Dip., EV, EE). The third looks fine apart a slight "ribbon" effect on one leaf.
The fourth is another one showing the problem, it's Spartacus Adorned (Tet., SEV, ML).
In the other slice of garden (you can't see it in the pic) there's another one showing the same problem, it's Nairobi Dawn (Dip., EV, EE).
All my DLs has been planted in march 2014. None of the twisting plant has go dormant. The ones that went dormant for a really short time are fine and the new fans are good looking.
I had aphids in october, and there are several leaves on some DLs that looks like someone is eating them up, but I don't really see any living creature outside during the day. Many leaves are old and dry.
Sometimes I have the urgency of cutting everything but I don't know if it could hurt DLs so I left them as they are.
For now I can't tell about the soil. The PH seems good, it's a very compact soil, you may remember it's very muddy and clay. There are armies of wormheart living in there. I would love to make a test for microelements, I saw some kit for home use but still they cost a bit. It's not the moment for my pockets.