If the group is running Master Looter and you’re not familiar with them, I’d not run with them at all. If they do not set any loot rules beforehand, then the ML infact is entitled to any loot that drops in the content.
If very clear loot rules are made, then a loot scam occured. But the loot will not be redistributed. One of the many reasons why ML is removed in Retail WoW due the large amount of confusions and petitions about this subject unfortunately.