are non-metalic cables approved for any electrical application???:roll: 
This is not a main. It is a sub panel located in one of the units of a 4plex. The main is outside by the lateral service entrance
Okay- so the discussion re: bonding screw is for not. If there is a bonding screw present, it must be removed.
If this is a sub-panel, it should have four wire non-the-less. If not, there is no way to carry the equipment ground to the panel, thus no floating ground. Unless, this sub-panel is fed from another building. But that’s a whole different animal.
I agree. I have some further questions related to the “two per entry cables” into one connector, and the size of the feeder wires.
If the connectors were designed for that use they would be permitted.
I am not calling this a defect, but keep in mind that this is a requirement that is often ignored.
If the wire size is 4 AWG or larger, the present standards require a temperature rated insulated bushing.
Just a couple of points think to keep in mind