Experiencing internal server error while trying to save my draft.
I thought it was a temporary problem but it doesn’t appear so.
You can check this link by yourself.
Try to translate something and click on “publish”.
After loading a bit the page says “Internal server error”.
hello @dag7, I can confirm/reproduce on my end 
I’ve submitted ISE when trying to submit a translation · Issue #6970 · mdn/kuma · GitHub to trace this issue.
Hi again @dag7, this has been fixed and I’ve successfully tested (I was able to submit an Italian translation -I removed it afterwards as it was only a test).
Let me know if this does not work on your side.
It appears to works, thank you, even if now I am unable to modify the slug of every article! 
Textfield to edit the text is just not present, I think it is not a normal behaviour…(or is it me? Is it hidden somewhere?)
Should I open a ticket?
the slug can be edited when you start a new translation. You have a box at the top of the page for this field.
Once the page has been published, you need to “move” the page. For this, I’m not sure if some privileges are needed.
No need to open an issue but please let met know if I can “move” page for you (given the current slug and the one you want), I’d be happy to help.