welcome to the forum.
i assume you’re looking at something similar to the below screenshot in the Android app, which shows the Observers tab on the Explore screen for all observations in Nanaimo, BC.:
in this screenshot above, the app’s Explore page appears to allow you to see observers beyond the 500th, with all observers beyond the top 500 having an observation count = 0. (in this case, you show up at #501, with 0 observations.) but what i think is actually going on is that once you go past 500, the app is showing you the same observers repeated from the top 500, but in a different order. (so that’s a little bit of a bug.)
you can see what i mean if you scroll further up the list… you’ll see yourself listed again in that list (at #271, with 10 observations, in the screenshot below):
(in other words, don’t trust anything shown on that screen beyond the top 500.)
if you compare the website version of the same screen (https://www.inaturalist.org/observations?place_id=27532&subview=table&view=observers), you’ll see that you would not even be able to see observers beyond the top 500. and it also shows you at listed around the same spot (#283), with 10 observations – so it’s consistent with the first 500 results shown in the app:
regarding the other thing you mentioned, if there’s an inconsistency between the observation counts that you see in this app’s Explore screen vs the observation counts that you see on a user’s profile page in the app, the difference is that this page (if you discount the problem related to observers beyond the 500th) counts only the observations that fit the filter criteria that you’ve set, while the profile page will show a count of all observations for that user. so you’ll see a difference in counts between the two pages, for example, for an observer who has only 5 observations in Nanaimo, BC, but 5000 observations in total.