Certainly a minority, but not sad 🙂
I’ve just checked mine and found lots of duplicates on caches I’ve adopted but almost none on caches I’ve placed. I’ve also got no duplicates myself, but lots of own caches logged where I’ve adopted them.
I think most are genuine errors and the four times in as many minutes may have been from a mobile phone.
As we have already seen on this forum there are COs who won’t delete a found log when the cacher admits not having found it, so I doubt if they will be prepared to delete duplicates.