task email notification

The assignment tab of user input task has the users or groups to which the task should eb assigned to. Check this tab if you have the 'Notify task assignees of new task via email and mobile push notification if applicable' enabled. 

Also, the corresponding process might have this 'Notify task assigness' checkbox disabled and then a custom email is sent using Send E-mail smart service. IF that is the case then check its configuration. 

AFAIK,
Users who see other members = Those members are in their Outlook/email contacts.
Users who see only themselves = Other members are not in their contacts.
Partial list visible = Only some members are saved contacts.

Email clients like Outlook automatically resolve email addresses to display names if they're in your contacts. If not in contacts, the client may hide or not fully display the BCC/group recipient list.

AFAIK,
Users who see other members = Those members are in their Outlook/email contacts.
Users who see only themselves = Other members are not in their contacts.
Partial list visible = Only some members are saved contacts.

Email clients like Outlook automatically resolve email addresses to display names if they're in your contacts. If not in contacts, the client may hide or not fully display the BCC/group recipient list.