This one cost me hours until I got how the system works. I deleted a whole bunch of templates!
Here's what I discovered:
When creating an automation, I can't take a template, build it into the workflow and edit it. Actually, the system lets me edit it, but I'm actually editing the original template, not the email I'm creating. What the heck?
A template should be useable, that's the whole idea, isn't it? Use a template and edit it according to your needs. E.g. use the same template for the whole automation sequence.
I can only consider it a bug. There's no logical way I should be changing a template when editing an email.