Some tests:

Case 1:

Start with emacs -Q

I insert

"
#+begin_src javascript
#+end_src
"

with point before "#+end_src", I press " C-c ' " to start editing the source

I enter "foobar" into the source buffer and immediately exit with " C-c ' "

Case 2:

restart with

"
#+begin_src javascript

#+end_src
"

I've included a patch that fixes both issues.

-- 
Le