I get the same error and in addition to get the error message that I have attached {Cannot update settings of task file Filtering-Task1.xml (project: AUDCAD)<br>Cannot invoke 'org.jdom2.Element.removeContent()' because '<local11>' is null}.
In my case the clone at the end also shows the error. I have attached the log file.
Closing and reopening SQX seems to solve the problem.