Actually, this is incorrect.
I received mine about 10 days ago and it’s fantastic. The liner attached to the carpet with Velcro. If you order the center piece at the same time, they attach velcro strips to the inner edge of the seat back portion on both sides. The panel has a hard plastic insert and works great when the seats are up.
The only potential downside is if you recline the rear seats at significantly different angles, but I have both of mine reclined slightly, and the same amount.
The center section hides everything in the cargo area and seems sturdy enough to keep a dog in the cargo area.
Overall, I’m pleased, but I wish the canvas went up the sides in the cargo area too.