Hint: Sing along with me. One of these things, doesn’t belong here
How well do you know the Code? Think you can spot violations the original installer either ignored or couldn't identify? Here's your chance to moonlight as an electrical inspector and second-guess someone else's work from the safety of your living room or office. Joe Tedesco, who has a knack for finding shoddy electrical work, did the dirty work and found this mess. Now it's your turn to identify the violation.
The wiring methods used in this connection are not compatible. As per 300.15 of the 2005 NEC, fittings and connectors shall be used only with the specific wiring methods for which they are designed and listed. Therefore, this installation violates the requirements of the Code.