While scrolling deep through Unknown in grid view, I often notice the same observation appears multiple times. It seems to happen around where I scroll to the bottom and a new batch of observations is fetched.
ex: https://www.inaturalist.org/observations?page=7&place_id=any&subview=grid&iconic_taxa=unknown - scroll down and when new observations appear, you should see a few images that are duplicates. if you hover over them, the URLs are the same. I’m using Chrome.
Bug documented at Github: https://github.com/inaturalist/inaturalist/issues/971
2016 - wow am I late to the party! 
I navigated here from this related (closed) bug report:
https://forum.inaturalist.org/t/duplicate-observations-in-search-results/38552
That bug report was based on Chrome and Firefox. I can recreate it using Safari 14.1.2 on Mac OS 10.14.6 (Mojave).
I have seen this a few times, and it annoyed me. At first I thought the observer had made duplicate observations, but this was not the case. I forgot to post it here, but apparently it is already in the Forum.
