I hadn't heard that. NOT GOOD.
It has been a while since I had WP do anything for me, in the past I never had a problem.
You can send it to the Cardone rebuild and return program.
call 800-777-4780 ext 4780 for details - They will commercialy rebuild it, not SS sleeve it.
Or try Steve Gregory at brakeboosters.com might be able to help guide you somewhere.