Originally Posted by
Chombi
Could be electrolysis between the CF and the Al lug occuring there, that's why the bubbling of the paint and clearcoat starts from the tube/lug seam and outwards. Not good if the corrosion extends to under the tube and the lug, as it will start attacking the glue bond between the two.
These frames had a fiberglass sleeve between the tube and the lug to prevent this problem. FWIW, the Trek bonded aluminum frames also had a tendency to develop cracks at the glue joint, for the same reason I gave above.