Distribution: 
   plain ubuntu 14.04 64bits (did not occur in 12.04)
packages versions: 
   gedit 3.10.4-0ubuntu4
   gedit-plugins 3.10.1-1ubuntu2

I have activated the completion plugin provided in the
'Edit>Preference>Plugins' menu.
When using a code snippet that uses variables to put the same text at various places, autocompleting this text causes a mess in the snippet.

Example: with the following test snippet

    begin($1) ... end($1)

suppose I start typing 'wh...' in place of $1 and 'while' is proposed by the autocompletion plugin, then if I press enter, I get something like

   begin(whwhilewhwhile)

instead of

   begin(while) ... end(while)

Moreover pressing ctrl+z to cancel yiels even messier results.