This story is gettin’ too crazy! 
Apparently, Wrecking Ball just joined the Junkers and is now attacking Busan with D.Mon, D.Va and the other MEKA crew defending the Busan base? Like Waaaaah! 
New Hero D.Mon Official Reveal! - Overwatch Season 4
Why would Hamsters do this?! What does he have against the South Koreans?! 
The Junkers found an omic crisis vessel hidden in Junkertown (it was Junkrat’s infamous “treasure”) that the Queen claimed and asked the hamster to make it fly.
(can read that here : Overwatch - A Friendly Rivalry )
We know that Mauga was sent to Junkertown to have a conversation with the Queen (can read that here : Overwatch - Vengeance Comes )
So yeah, something happened of-screen to make them attack Busan and probably stole the EMP that was meant for the Gwishin on MEKA base, but I think we’ll have this story told very soon, and I definitely hope we’ll see Mauga meeting the Queen because if we don’t, I will be very disappointed (and I won’t be the only one)
Awesome stuff Gwadael! 
This is all very interesting! Looks like i have a lot of reading to do. 
I really hope the Devs show all the meet-ups between the heroes. We need this. 