This is a minor issue with no real impact, but it is better to be aware of it.
Only in Opportunity List View and only if you chose to save the filter settings: if you click the Select Users button and your filter is not set to All users, the Select User window might show you other users selected than those who are really selected. This is a known issue. Because we cannot fix this issue, we added a text label next to the Select Users button, showing really which users are selected.
Here is the real selected user...
...although this is what will appear if you click the Select Users button...