Hi Thomas,
Does your QA environment contain any other projects? If so do they contain that same rule that you are having an issue with? It could be that if the rule exists in another project, but within the environment then IS might be having an issue. One solution could be to make that rule instead of being approved into its editing status and retry to import the KDD.
I usually turn off auto-approve just so that I would not have all the rules that I ever created in every single project in IS.
Try to re-import the KDD, but make sure to select the overwrite option. That could help you overcome the issue that you are having.