I’m signed up with the Meetup platform, and it only has my spamgourmet address. I have the .com and .org form of the company name as Trusted Senders, and I’ve never received mail from them from any other domain, except from one group on the platform.
The emails from this one group omit the part of the sender address before the “@“ that normally looks like the sender’s address, i.e. if the sender is info@xyz.com, that part should look like .info#xyz.com . These emails are decrementing the message counter. All my other emails from Meetup arrive to my protected email account without decrementing the message counter, and they aren’t missing that part of the sender address.
This looks to me like something that is happening before it arrives to Spamgourmet, but I’m not sure I understand. I think the groups can only send email via the platform, and I doubt they’d even have access to the subscriber’s email address unless the subscriber gave it to them. Furthermore, if this is an attempt to filter spamgourmet, for one thing, they’re doing the opposite and getting themselves filtered, and another thing, why would it only be a certain group?
Also can someone explain to me what the alpha-numeric string constant in the middle maps to? (After the SG username and before the sender email address.)