ShinyRabbit94 - The github issue reported by SuperiorPanda77 is a display issue - meaning the files are deleted, and only the "undefined" display is incorrect. This should be fixed in the next release (1.4).
In your case the files are not deleted from the filesystem - so I assume this is a different issue. Can you provide more info so that I can try to reproduce:
How are the artifacts created? Are the links in the popup describing the un-deleted files correct? Can you add a screenshot?