In the attached video of a cracked garage door top panel. I come across this defect quite often during home inspections. Improper adjustment of the garage door tracks and/or the drive chain can result in jerking of the door during operation. The jerking can result in flexure at the center of the door when the panel is in the horizontal position. There is a lot of stress at the connection point where the chain drive is connected to the garage door.
If your garage door is flexing or jerking during operation, contact a local Rochester or Southeastern MN contractor specializing in garage door installation.