I didn’t know this, but the php function json_encode() actually adds quotes to any string you encode.
I was submitting some values with Ajax.InPlaceEditor, and in the php side encoding my return string with json_encode. Well, it was returning “value”, and adding it in the div. But the value inserted in the database was not quoted.
I thought it was the Ajax.InPlaceEditor. A frustrating thing to not know.