Alright, after a lot of digging I figured it out myself:
This problem occurs if you anonymize IP-Addresses, which seems mandatory in the EU. Because of the anonymization a lot of IP addresses look the same and the contacts get merged. So you can either:
- Disable IP-Tracking completely - If “Ip anonymize” is enabled, this is not possible via the interface, only in app/config/local.php => ‘track_contact_by_ip’ => 0. You can also deactivate “anonymize IP”, then deactivate “Ip Tracking”, then activate “anonymize IP” again.
- Use this fix, which is not yet merged with the core: fix: lookup contact by ip in mtc.js tracker *except* if anonymised by donbowman · Pull Request #10380 · mautic/mautic · GitHub
This Thread helped me out: