Just had a DC40 in with same problem. Looks like this will be a common problem. The wire are actually being sliced or cut, unfortunately this job had to be a fast turn around, so I was unable to try and see what was cutting the wires, but it doesn't look like it is just due to flexing. Couldn't figure out how the cyclone assembly came apart. Pulled, tapped , twisted, nothing!! A blast with the air line cleaned it up well though.