This behaviour occurs in FireFox 34.0 but not when I tested it in Chrome.
When copying text which also includes a template the selected text is deleted rather than copied upon using ctrl+c. By contrast right-clicking and selecting copy works as expected.
- Using Firefox go to https://en.wikipedia.org/wiki/User:Andr%C3%A9_Costa_%28WMSE%29/test3?veaction=edit
- Select the e-mail address and press ctrl+c