Session timeout never occured on Confluence Data Center

Summary

Session timeout never occurred on Confluence Data Center.

Steps to Reproduce

1. Install Confluence Data Center on two nodes with following this document
2. Change <confluence_install>/confluence/WEB-INF/web.xml on each node as follows (Set session-timeout to 1 min)

   <session-config>
     <session-timeout>1</session-timeout>
   </session-config>
   

3. Start Confluence

Expected Results

Session timeout should occur in 1 min on web browser.

Actual Results

Session timeout never occured.

Notes

This problem occurred only on Data Center version.
Is it related to CONF-26796?