We have followed the Identity Portal documentation to set the timeout in portal to 8 hours, while the timeout in Identity Manager works, the Identity Portal timeout is not taking effect.
Release : 14.5.1 CHF1 and below.
Component : CA Identity Suite Virtual Appliance
Engineering provided a hot fix to resolve this issue as part of defect DE619656.
Hotfix is part of 14.5 SP1 CHF2.