Copy-paste subtask in same task weird behavior

Following of bug #496680
You can get weird behavior if you copy-paste a subtask line in a same task.

Steps to reproduce:
Create a task with the following content:
test
- sub-test
-

then select like this: http://img690.imageshack.us/img690/1821/capturetest.png
Copy and paste without changing the selection.
Expected behavior: text unselected, no modification of task.
GTG's behavior: got a few different results from the exact same actions, here's an example:
http://img15.imageshack.us/img15/4479/capturetest1.png
and another one:
http://img10.imageshack.us/img10/5791/capturetest2.png

Hope this helps.