Hi Yoro,
do you click on a physical phone button or on the button in the WebUI.
As far is i know, the OpenScape Contact Center does not support hang up funktionallity of the related button in the WebUI.
If you do not use wrapup time (which is used to give the agent time for the data maintenance before he continues receiving calls) the Counter shoud end after the call.
It seams that the OpenScape does not work propperly.
For more details you can take a look into the Log:
Transaction CRM_ICI_TRACE
You have to set the User Parameter CRM_ICI_TRACELEVEL to value XXX to enable the logging.
Good Luck!
Kind regards,
Martin Gaschk