Originally Posted by
Nolan Kienitz
Not sure if it was for ... or to hold up the plumbing ...
To hold up the plumbing.
That slip joint slip nut looks like it is barely on the discharge pipe (others have mentioned it being cross threaded, but that's a minor problem

), and, because there is very little pipe into the slip joint, the force of the disposer's discharge likely blow the slip joint off the end of the discharge pipe.
Should have used a tail piece extension to get a good fit there.
Cheap stainless steel sinks? If so, any small vibration from stuck debris will be exaggerated as the bottom of those cheap SS sinks allow the disposer to oil can around.