I work in the industry, if you work the small Airbus regularly it's likely that you will come across this either as a scheduled check or when a leak occurs.
Airbus are very good at hitting common faults hard with preventative maintenance and improved parts.
The SIL I mention is an Airbus Service Information Letter that details these leaks and the schedule of inspections required along with all the part numbers and photos of in service findings.
I can't send you the document but the general gist is in my last post.