Hi,

When you send an email from the chatter without selecting a specific email template, Odoo does not use a normal email template like Sales Order or Invoice templates.

Instead, Odoo uses its internal mail notification layouts.

Usually, chatter emails are wrapped by layouts such as:

• mail.mail_notification_light

• mail.mail_notification_layout

The simple chatter composer and the extended composer can use different notification layouts, which is why the received emails may not look the same.

So, if you want to customize this, check the technical views, not only Email Templates:

Settings → Technical → User Interface → Views

Then search for:

• mail_notification

• mail.mail_notification_light

• mail.mail_notification_layout

In short: chatter emails are normally using Odoo mail notification QWeb layouts, not a standard email template unless you manually select one.