That shouldn’t happen, templates should not be registered. Please submit an issue at Issues · GDevelopApp/GDevelop-examples · GitHub
In the meantime, you can try to follow those steps
- Close GDevelop
- Back up your project file
- Open your project file in a basic text editor like notepad
- Remove the
projectUUID
entry which should be among the first lines - Save the changes
- Reopen GDevelop