I have been having an issue with variables in the project named the same as those in step templates. As a work around in the short term I decided to save the community step template to our instance and make the necessary changes myself.
As I had to do that, the name of the template needed to be changed. So I decided to include some identifier that this was a community written, but organisation updated template with  at the start. This allowed me to save the template fine.
When I came to use it, I am unable to do so because  are not valid characters in a step template name. I would have thought that if that was a constraint, that would be validated on creation, and not allow a user to create a badly named step template which they could never use.