Ok. Can you confirm if this address belongs to MCM?  bc1qaamrxr0s469970e9m9tea4d9ssa7vfd7uq9cqk
It's strange because the fees were accurately distributed to a separate address as well.

Do you (or does anyone) have any ideas how this could have happened -- this could potentially really help other users not face the same issue.

Things to rule out:

Malware (did a malware search)
Cloned site (Was using PureVPN and incognito mode)
Tor exit nodes (Was using Google Chrome on the main site, not onion)
Browser add ons/"computer programs" (Have none besides Adblocker and I also have sent multiple transactions within a 2 hour space and this one was the only one affected)