When I try your two queries, I get a total of 3496 for the first query and 3520 for the second, an error of 14 caches. Why this changed from 24 caches I am not sure.
However that is working, as you did, from the summary report just above the map, with the report for the multi-finder example showing:
The 9 caches that only PnavE_81 has logged
The 2718 caches that none have logged
The 769 caches that some have logged
However you missed one other line, caches that everyone has found, which is shown in the table below the map and consists of 13 caches, which resolves most of the error.
So yes, there is a bug, a fourth summary line should be added above the map "The x caches that everyone has logged".
This leaves an error of just one cache. To find that one cache would involve exporting to CSV, importing into Excel and doing some simple analysis.