This is is pretty easy to repro at least. Open a project based on third person. Find the default starter map in the content browser, right click and pick Duplicate from the menu. Type in a new name and press Enter to crash.
Hey Furroy -
Thank you for your report. We have identified this issue previously and have an internal branch with the fix applied. This fix is currently being tested and will be pushed out with one of our next engine updates or preview releases.
Thank You
Eric Ketchum