I'm receiving emails not addressed to me

Its been 2 months now since i noticed this and raised it with Microsoft support. 
I'm an office 365 admin and i noticed that some of us that belong to a certain group receive emails that weren't addressed to us. We're not in the TO, CC or BCC field. I've run several traces and sent to support but still no luck. 

I've collected sample emails from the senders mailbox for investigation.

I've checked the rules on the admin center but nothing is configured to forward emails to any group account. Like i said its 2 months of back and forth, phone calls, remote sessions, email exchange and I'm frustrated. so far I've had to deal with 4 separate support agents.

Has anyone experienced this?

If not, is there a way to escalate to a senior support person who might be an subject matter expert?

Thank you