OK, forgive me for resurrecting this old topic, but the same thing has happened to me in ACAD 2010.
In the CUI config menu, it shows as still enabled.
They still work in the command line and within the MTEXT editor to copy & paste text, but not for AutoCAD entities unless I use the copyclip, cutclip, and pasteclip commands.
Those commands do still work from the EDIT menu BTW.