Currently when viewing applications in a task sequence the revision number is not displayed or validated.

If an Application revision is deleted the task sequence will keep trying to deploy the deleted version until it is removed and added with the latest revision.

Having it displayed in a column or validated when opening the task sequence would help reduce time spent troubleshooting this problem.

http://www.vansurksum.com/configmgr-2012-caveat-with-application-revisions-when-used-in-a-task-sequence/