Thanks a lot for bringing this tricky issue to our attention!
The issue is fixed with V7.0 .16, which is now available 
It actually has two fixes:
- The new version requests the “Write to Clipboard” permission from the browser. This prevents the issue in most cases.
- If installed, the clipboard feature uses the XModule2 now. This is the most robust solution. It solves the issue in all cases.
This is how the new clipboard settings page looks after the update:
