This second part of this note in DO188 guided lab is incorrect:
This is not true. The changes will persist if the container is restarted or stopped (and then started), as seen here (performed in the RHALP lab environment):
The changes will not persist of the container is deleted (removed).
(Creating another image from the same image is creating a new container. Once a container is removed, it is gone.)
This is said (but not very clearly for someone who is reading this for the first time) in section 2.7: