Thanks, I will give them a call and see what they say.
I'm thinking the tech that did your service is to blame for this.
He probably topped up the fluid, and either overfilled the reservoir or simply didn't clean the area around the cap after topping up.
I also think the reason the dealer didn't want to put a claim in is that Ducati would deny it and they'd get stuck for the parts cost.
It is still a good idea to call DNA.
It would probably be a good idea to look for a new dealer also.