We have a servlet filter defined to do redirection. It redirects from /path/a to /path/b , very straightforward. The from path does not exist and the to path might be external or internal. Today we noticed that on 2 servers in the farm the redirects were not working however on another it was (this has been in production working for months). We restarted the 2 that were not working and one started working again. The final one required another restart to get it working. Anyone have any idea why sometimes the filter seems to not be in the chain but a restart and no code changes fixed it?