I have a problem with Python src blocks indentation.

At the moment, I export IPython notebooks with ox-ipynb

(https://github.com/jkitchin/scimax/blob/master/ox-ipynb.el

from scimax by John Kitchin)

All the lines but the first one in src code blocks have 2 superfluous leading spaces.

If I set 

(setq org-edit-src-content-indentation 0)

then the code blocks are ok.

Any idea where to look for to track this problem further down ?

Best regards,

Fabrice