NX licenses will not be returned immediately after exiting NX, but after approx. 15 minutes the return takes place.
When trying to remove these licenses with lmremove, it does not work completely: the license always remains in use, it cannot be removed.
An antivirus software of Symantec Endpoint Protection (SEP) is blocking the release process. After deactivating SEP, it works fine.
Notes and References
OS Version: 764