If your dog is allowed to lick at the interdigital cysts, or there is excess friction when the dog walks, or something causes them to break open, they certainly can bleed. These can bleed just like any other delicate injury.
If there is never any friction on the interdigital cysts, they might never bleed at all. Some type of friction was probably involved in their creation in the first place. Unfortunately, these are on the dog’s feet.