In some places, our featureclass has stacked points derived from identical XYs. We published to REST through ArcGIS server and added it to a web map (here using Map Viewer Classic, but same problem in Map Viewer Beta).
When the point is clicked in the center, 4 pop-ups are displayed.
When clicked on the edge of the point (or a bit out beyond) only 1 pop-up is displayed.
We are concerned that we could be called out for misinforming the public.
I can see how this behavior is unexpected and misleading--a Support case might be helpful to discover scope, workaround, and details to support review at the engineering level if required.
Another option to consider is enhancing your public map with tools focused on highlighting feature count and density using symbology or selection tools.
Two possibilities which come to mind are Clustering and the Select Widget in Web App Builder:
Select widget—ArcGIS Web AppBuilder | Documentation
The first allows end users to select features by drawing a box around their area of interest. The second symbolizes based on how many features are nearby. There's a helpful clustering visualization at this link:
I hope you find these helpful!
We are using Experience Builder. I tried enabling the select tool on the map, but selecting the points didn't open the pop-ups. Using the point option for the select tool does consistently select the same (correct) number of features though. We really would not want our users to deal with the complexity of the select tool. If we could configure it to open pop-ups and be active by default then it might work.
Our data are not in either the WGS 84 or Web Mercator coordinate system, so clustering won't work at least until it supports our coordinate system. I don't think clustering would work in our case anyway, but without trying it, I can't be certain.
This is a known behavior or limitation of the application. Clicking the edge of any point, only displays the top feature.
As a workaround, click the center of the overlapped features to display the overlapped features attribute.