Players leaving M+ keys while I'm trying to improve mine Key

at 3:30 this morning my guild leader was helping me improve my M+ 7 Mai Caverns my guild leader used the own skip path to the first boss. one of the dps players from Area 52, just left the instance before the player leaving reported my guild leader who was helping me with the key with doing this automatically made my key go from a +7 to a +6. from this action my guild leader received a notice to the world of warcraft authenticator which they have said it’s the first time in 20 years that they have received this action. It not World of Warcraft how players simply get away with doing this, it’s not The World of Warcraft. Can I have an Dev from wow to look into this action and matters similar.