I had post this a few days ago, with the similar problem.
Once a custom template saved, and closed the page, you can’t find this template any more. If you create a new template with the same name, it will say the template has existed, please use another name. But you can’t load the previous template you have created. Means you can’t edit the previous custom template once you closed the page you just created the template. It do existed and works but can’t load and edit it. If want edit and change something, you need just load the name and deleted, then create it with the same name again.
For editing in the future, you need always backup your custom template in somewhere with notepad.This make users very trouble.
Allowed user create custom template, should allowed load it and edit. hope better in the new version.