This appears to be a known issue in the 12.x verisons of ALM. Please reference QCCR1J78648.
Appears that this issue is under investigation for future release fix.
HP does offer an attempted workaround as follows:
***Unlock components by removing and adding the user to the project or removing the component through direct database manipulation.***
I would try the remove and add back user method before attempting direct database manipulation, as that opens to the door to certain risks if mistakes are made.