Disable SysLog Configuration in /paradmin System Status & Settings > SysLog Configuration. You can temporarily turn off "Enable Syslog" for both user and sys-admin activity. Once you have done this, create a new backup on 2.3 and then migrate to 2.5. Once complete re-enable the syslog functionality on 2.3 and 2.5.
Waiting for fix in a future release of TPAM .