The main page for observations should not show observations that 404. I am not sure how often this happens because this is the first time I am seeing this, but it should be possible to check that observations haven’t been deleted before showing them on the landing page.
they do some caching of results. so i think it’s inevitable that you could end up with some things that have been deleted by the time you click on them. it’s also possible that someone deletes an observation after you load the Explore results.so then when you click on it, you don’t find it. so i’m not sure this is a bug exactly.
do you see this often enough that it’s a big deal? if so, maybe instead of showing just a generic error message, they could provide a more plain language explanation of what could have happened?