@ngx
The issue you're having is the exact issue I'm having. For some reason, as I am adding, editing, and tweaking my IR parts, the groups they reside in are being constantly duplicated. At some point, the IR Editor Window will have so many duplicated/empty groups that using the editor effectively is impossible. Deleting one of these duplicated/empty groups can take up to 25 seconds to do at a time and has led to the game crashing. This has made big projects involving complicated IR setups no longer reasonable.
Below is a screenshot as an example of this issue. All of these parts are uniquely named, so any parts with the same name are duplicates.