If I'm converting a map from 10.98 to 8.0 for example, I get these "artifacts". Completely red items that is almost impossible to remove. If there are many of these it can take a very long time to remove them. Make it easier to remove these.
Edit: the video doesn't show it but I clicked on cleanup.
Edit 2: Works when I used it on a map with "less" cleanup. Maybe there is a maximum amount it can remove?