Rear side glass or rear liftgate glass? If side glass the same side as the sliding door closing, then maybe something was binding a little to cause the window frame to flex and crack the glass. The sides are tempered, so any kind of impact or stress will make it shatter everywhere.
Nice to know Safelite is consistently bad. Every windshield we had replaced by them cracked. Our 2005 Magnum went through 3 windshields in 2 years. The windshield in my 2000 T&C lasted 7 years before it started cracking from the bottom, out of nowhere. It has grown completely across to the driver's side, split and gone up and down and I'd probably be pulled over for it if I drove it. When they were going to replace it, I wanted to do all the disassembly work first and only have them put in the glass and molding. My wife wouldn't let me, and said they are professional and guarantee their work.

Yeah, guaranteed to be bad! I looked at the van after they left and all 6 of the special nuts I had put on to hold down the plastic cowl were gone. I will only go back to them if I have no other choice.