The easiest way to see this is use carnage and strang3 together. Basically if an enemy fires an ability it will go carnage animation strang3 animation. Then another ability fires and instead of showing a banner it shows carnage ability then strang3 ability again. I’m guessing it just keeps track of the last ability to fire instead of if the ability has fired at all in the turn.
The other thing is using like coulson with 5* Hawkeye. Multiple countdown tiles go off and it greatly lags the turn as it does one banner waits a bit does the other then it does the original etc etc. If that could be as quick as say the same ability (like recharge or speed shot) triggering that would be great.