Apple’s "Protect Mail Activity" is a powerful feature designed to enhance your email privacy by masking your IP address and preventing senders from tracking your email activity. However, when combined with Pi-hole, it can lead to unexpected delays in email delivery.
As default Pi-hole is processing IPv4 DNS requests. But nowadays your local clients receive also IPv6 addresses from your Router. So your clients are able to request IPv6 request, which would be bypassed your Pi-hole. This would also explain the “strange” behavior, why you’re getting furthermore some adds.
This article is about Privacy Settings within Pi-Hole. If you want to disable logging for certain reasons for example to save disk space on your little raspberry pi or to be complaint with any necessary privacy requirement, then is could be a interesting article for you.