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.
To reproduce:
Also tested with the {{!!}} template to ensure that it had nothing to do with the {{@}} inserting an image.
I can reproduce this in Firefox 34.0.5 and 35.0 on my Mac 10.8.5 but not Safari 6.2.2. Also, it doesn't actually appear to copy or cut the selected text, because when I paste, it's not there. It seems to be working more like a delete key.
The same problem appear to happen when you use ctrl+x (or ctrl+c) in a bullet point list. (Also in Firefox).
Confirmed: cmd+c for highlighting the text with templates(any template) - the text disappears when trying to Copy it with a keyboard shortcuts and cannot be pasted with cmd+v. Undo works though.
Right-click Copy/Paste works as expected.
About bullet point lists problem - cannot reproduce. Some specific steps/details?