Sometimes customers see a discrepancy in the unsubscribe numbers in their instance. This is particularly puzzling to some who are using a custom unsubscribe process that is not trackable in Marketo, since you would expect to see 0 unsubscribes in the Email Performance reports. However, this is not always the case. That’s because if Marketo receives spam reports directly from the email provider, it automatically unsubscribe that person in your instance. This also means that if you look at the number of people who clicked the unsubscribe link in Marketo when you are tracking the unsubscribe link, you may also find a discrepancy.
Leads are automatically unsubscribed due to default feedback loops setup with the ISPs listed on this page.
You can use the following filters to find leads that have clicked the SPAM button in your emails:
Filter 1: Data Value Changed
New Value: True
Reason: Contains Customer complaint received from ISP
(Optional to Specify what Email Domain)
Filter 2: Email Address
Email Address: Contains, @domain.