Is reported that (AtrsHost) Altiris.ClientTask.Server.ClientTaskServer.ProcessPostClientStatusXml will error out if task status return has invalid characters.
In this particular customer environment the following error was observed within the SMP logs (also acting as the Task Server for endpoints)
"Status XML is badly formed. Exception: System.Xml.XmlException: '', hexadecimal value 0x08, is an invalid character. Line 36, position 52."
There is a 'Run Script' Task within the job sent to the endpoint. The Run Script had the advanced setting of 'Save Script Output with task Status' enabled, that will include all onscreen output from the script to be included in the status XML to be sent back up to the Server for processing.
In this scenario, the command 'timeout' was used. "timeout /t 3" and this was producing invalid characters as output that was captured.
Make sure if this advanced option is enabled 'Save Scrip Output with task Status' all commands within the run script does not introduce any invalid characters.
The resolution to this particular scenario was to utilise the command line option to the command 'timeout'
i.e. timeout /t 3 >nul
'>nul' will stop the timeout from outputing invalid characters.