Okay, folks, what happened here?
LUCKILY, luckily, we were in the middle of dinner when this hot water supply under the kitchen sink blew apart. If we had been gone...
I put this in only about a month ago. It hasn't leaked one drop since then. Our water pressure is only 40psi. Before moving to this house, I had never even seen this type of supply line. So what did I do wrong? As you can see, the pex line just blew right out of the compression nut. The ferrule (or whatever it's called) is the plastic kind that came with the pex line. It looks like the line is plenty long enough. I figured if it wasn't leaking it was tight enough.