When running job AL2QSVFB to stop the AL2QXVFB task, the process is not being killed and therefore the task doesn't terminate.
The following messages comes out of the task: (where 1234 is the port # specified)
Stopping Xvfb using server/display :1234
Did not find the process running with 1234
Release : 12.1
Component : 7UI
Verify the USERID that is assigned to the AL2QSVFB task to kill the process is the same as the USERID assigned to the AL2QXVFB task that is running process.