The last months I have experienced a growing leakage of water into the backlights in the rear door on my 2000 Legacy station wagon. When I opened the rear door after a rainy day, the water streams out of the lamp holders.
I complained to the dealer where I bought the car, but he insisted that this was completely new to him. As a smart guy, I had my son in law who is in the car business to raise the problem to a dealer in a different town, and...yes this was a well known problem, an he had replaced several units (The complete Plexiglas assembly containing both rear lamps) and if this happened within 5 years of purchase, it was covered by Subaru.
For me it was 5 years and 2 months, .... so sorry.
Todd, Norway