The Mavic's camera does not have a hardware infinity stop, and relies on software for focus.
There are two problems with continuous auto-focus that stem from the fact that the software can only tell it is in focus by shifting focus slightly, every few minutes. The first problem is that there will be a slight de-focusing every once in a while. The second problem is if the center of the field has no detail, this could cause loss of focus.
Setting the lens to infinity seems like a great idea, but since there is no hardware stop, this tactic has the problem once again of risking being always out of focus, for example a temperature change may change the focus. This is similar to the horizon tilt issue.
So, for now, manual focus is the solution and it needs to be part of your routine, even if you have AFC enabled.