It is possible that your browser and its extensions add some content within the source code of the email. To check this, go to Exit Screen / Send email & click on source.
As in the following example, some content can be added within the HTML code.
As a consequence, an email Title is added as soon as there is some custom HTML. Emails are triggered when they have content + titie.
To avoid this, make sure that you delete the title & all the content in Source, than save.
Without extension, this is how the generic html should look like.