In this view your emails are sorted by EEMINDER DATE, not received date.
This lets eeminders show you what you plan to work on at the top. You can see that your emails are sorted by eeminder date by the little downward arrow next to EEMINDER in the column header.
As a result the groupings are also by eeminder date.
Emails with no eeminder date are all displayed under the title of NONE. However within this group they are sorted by reminder date.
If you want to view your emails sorted and grouped by received date you can always click on the Received column header (clicking on the column a second time will change the sort order from ascending to descending or vice versa).