If the session settings has not been done on the warfile level then it become default every time you apply the patch or wdeploy
Applying patch redeploy the warfile and all the settings goes off.
- Navigate to BOE warfiles directory (E:\Program Files (x86)\SAP BusinessObjects\SAP BusinessObjects Enterprise XI 4.0\warfiles\webapps\BOE\WEB-INF or similar).
- Take a backup of web.xml file. Open it in editor such as Notepad.
- Search for the following in web.xml file:
<Session-timeout>20</session-timeout> - Increase the value as required.
- Redeploy war files with wdeploy.