My Canon doesn’t focus like that with the timer. Remote shutter release yes, Timer no.
Could be that they were going to get a crappy out of focus picture and they got a lucky shot of a rodent.
All auto focus cameras - both digital and film models - focus before the photo is actually taken. Generally, the focusing takes place when you press your camera’s shutter release button halfway down. That causes the camera’s lens to focus on whatever is in the center of the frame when you begin to press the button.
So here’s how you use focus lock. Before you actually take the photograph, place your subject dead center in your viewfinder. Press halfway down on the shutter button, but just halfway down, so the shutter doesn’t go off.
By pressing halfway down, you’ve locked the focal distance on your subject even if you move the camera, as long as your finger continues to hold the shutter button halfway down. As long as you continue to press the shutter button, the focus stays set at the distance you’ve “locked in,” which is the correct distance to your intended subject. So now, with your finger still holding the button halfway down, reframe the picture in your viewfinder the way that you want it, with the subject placed off center. When you have the composition set the way you like, you take the picture by pressing the rest of the way down on the button.
Presto! Your subject is fully in focus even though you placed it off center in your picture.
Works that way on my Nikon ... yours could be different.
This is my theory...
One of out couple set the focus on the other while they were sitting their. he/she then set the timer. This persons body coming back in to frame set the auto focus off all over again. The sound attracted the aforementioned rodent who insinuated it's self in the foreground again messing with the cameras mind. The camera then focused on the nearest “face” and SNAP! A star is born.