This is caused by an old EventListener summaryExportListener that was used when exporting summaries to the report once it had been generated. This was rewritten to not having to use an EventListener somewhere between 2.0 and 2.1.2 and someone forgot to remove the part where it attempts to remove the listener. This is known and has been cleaned up for the upcoming 2.5 release.
tl dr; This should in no way be affecting anything related to your own scripting or anything else for that matter. It simply clutters the command-line printouts a little and the fix has been scheduled for the next big release.
Mikael
SmartBear Software
