Possible reasons
The customer data matched completely
The two profiles shared the same email, phone number, and device.
Consistent data came from the same device
Non-conflicting data was entered from one device. For example, a customer first subscribed to web push notifications, then later subscribed to an email campaign from the same browser. Maestra treats this as the same person and merges the profiles.
A merge operation was called
The customer merging operation was triggered, and the profiles were force-merged. The higher-priority profile is specified explicitly in the operation call.
Manual merge through the admin panel
An operator merged the profiles manually through the web interface of the admin panel.