Currently the daily unique opens in the Email's report has the following formula "New customers who opened today the email" without excluding the customers who already opened the email before. The correct formula should be "New customers who open the email at that day BUT DID NOT open it before".

We already opened a support case with Microsoft and they refuse to fix it, as they have mentioned that this is how the report is designed and we don't have plan to update it, and you can open an "idea" instead.

To reproduce the matter:

1. Open an email that was already sent in a Journey > Reports tab
2. From the chart/tile, press on "More Commands" (...) > show as table
3. Export the table to excel > calculate the "Total Unique Opens" - here you will have the total number
4. Go to the "Related" journey > press on the "Send Email" title where the email is attached to
5. From the "Analytics", press the "Delivery and interaction details" > Interactions tab
6. Here you will find that the Total "Unique Opens" doesn't match the total Unique Opens of the email report

As per Microsoft support, in the email report, they aggregate the total unique open per day without checking if that customer already opened the same email before. This is completely a wrong formula and currently the email report is useless if that formula is not going to be changed.