For me at least it's a classic, usually camera-lens perform very well and nail the focus for each and every shot except the critical one you have been awaiting.... all my cameras will usually do something to ruin the best shot.
Once I was shooting a wedding with 5D 24-105 and speedlight, the shot before, the shot after were perfect the critical shot, the flash was recycling and the camera chose a lengthy shutter speed of 1/2 a second ....
At least you weren't as unlucky as this guy
https://www.youtube.com/watch?v=pGLmdQuxW_s
Once I was shooting a wedding with 5D 24-105 and speedlight, the shot before, the shot after were perfect the critical shot, the flash was recycling and the camera chose a lengthy shutter speed of 1/2 a second ....
At least you weren't as unlucky as this guy
https://www.youtube.com/watch?v=pGLmdQuxW_s