The documentation also mentions that it may not pick up small branches (especially as we move into winter). Also remember that OA raises the altitude on the Mavic, and it does not have cameras that point upwards.
Similarly, I was under the impression that OA on the P4 also moved around objects instead of just above them, but I haven't seen any mention of that on any discussion of the Mavic's OA. Not sure if that's an intentional difference, or just a 'given'.