@isoparme make sure you use the tester at https://jsonpath.herokuapp.com/ as suggested in the documentation to test your expressions. JSONPATH never failed - the expression is invalid against that string, so openHAB returns the entire JSON string instead.
thanks my json (in reality this is a [dictionnary] python ) is correct , so i uninstall and re-install again jsonpath , and now my rule run correct again , really wierd … but that again for your help