You are the best! I was looking everywhere and your solution was the one that worked:
body_is_html=True, is the key to make it work in Odoo v17.

Thanks a lot!

Hi,

tracking=True does not work with HTML field. if you need log the that field change in to chatter. you can override the write function of the model that contains the field, and post custom message in to chatter when writing in to that HTML field.

Example

def write(self, vals):
    if vals.get('field_name'):
        self.message_post(body="Field Name: %(old_value)s --> %(new_vale)s", old_value=self.field_name, new_value=vals.get('field_name'))
    res = super(ClassName, self).write(vals)
    return res

Regards