I'm running Jasper Reports Server 5.5, upgraded from 4.5 under Tomcat 7.0.47 and Apache 2.2. When using Apache to proxy the server, I get an escaped percent sign in the report path. Running from Tomcat everything is fine.
Notice the extra 25 (Escaped percent sgn) in front of the 2F.
The 4.5 install works fine both ways.
<span style="font-family: Arial, Helvetica, Verdana, 'Bitstream Vera Sans', sans-serif; font-size: 15px;"> ProxyRequests Off</span>