Cloning a template from
"Template OS Linux"
to
"Template OS Linux (Relaxed)"

results in an unhelpful error message.

Ideally, as I enter characters into a field, I should be immediately informed (in a non blocking manner) that the field is no longer valid.
If I try to submit, I should be told what characters are/are-not valid, so that I can make a correction that won't also trigger the same error.