Last box I received (this week) was really damaged and I had to sign a damage report.
During that time I actually had a chat with the delivery guy about this issue. He said that the problem is that the warehouse workers are picking up these packages using their fingers in the openings/gaps on the edges of the box. And it usually snaps after a while.
Queal is packing these using one tape over the middle only. So the general idea would be to reinforce the edges of the box with extra tape.
Hard to explain really but hope you understand what I'm saying