Segment email: Mautic claims XX out of XXXX emails were read whereas it wasn't true

Your software
My Mautic version is: 4.4.7
My PHP version is: 7.4.33
My Database type and version is:10.5.18-MariaDB-0+deb11u1

Your problem

I’ve set up 1000 testing accounts on our gsuite domain that we use to test our emails before attempting to send them to real people. The queue system is used instead of sending immediately.

Here is the bash script (cronjob) that runs every minute

For some reason Mautic shows that out of 1000 emails (segment email) XX were read. As Amazon starts sending out emails the number of “read emails” keeps growing until it reaches a certain number. The first time it was 50+. The test I ran today showed 125 read emails.

If I log in to one of these affected gmail accounts I see that the mail hasn’t been read yet. If I click on it and read it Mautic doesn’t count it as “reading” coz it already thinks this email was read.

If I login into other testing accounts and click on the email Mautic detects it and increases the “read emails” count.

What could cause this behaviour?

These errors are showing in the log:
None

Kind regards