It's possible to see higher volumes of unsubscribes from prospects using Gmail. Google supports the list-unsubscribe header. When the Gmail unsubscribe link is clicked, the HTTP method used by Account Engagement results in Gmail linking you to the sender's unsubscribe page where you can finish submitting your unsubscribe request.
We prevent most email bots from unsubscribing via list-unsubscribe headers as outlined here:
▸▸ https://help.salesforce.com/articleView?id=000273384&language=en_US&type=1.
000382982

We use three kinds of cookies on our websites: required, functional, and advertising. You can choose whether functional and advertising cookies apply. Click on the different cookie categories to find out more about each category and to change the default settings.
Privacy Statement
Required cookies are necessary for basic website functionality. Some examples include: session cookies needed to transmit the website, authentication cookies, and security cookies.
Functional cookies enhance functions, performance, and services on the website. Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual.
Advertising cookies track activity across websites in order to understand a viewer’s interests, and direct them specific marketing. Some examples include: cookies used for remarketing, or interest-based advertising.