It looks like the server doesn't process all the clicks that the client does. This is most visible when you use "raining gold" on a boss. After it's done (with the boss still being alive and well), as much as 75% of the gold gets removed again. This seems to be a bit more than you might expect from a slight timing difference between the client and the server.
I also see this on other occasions where you get a crit which is more than enough to kill the monster, but nothing happens.
It looks like the server doesn't process all the clicks that the client does. This is most visible when you use "raining gold" on a boss. After it's done (with the boss still being alive and well), as much as 75% of the gold gets removed again. This seems to be a bit more than you might expect from a slight timing difference between the client and the server.
I also see this on other occasions where you get a crit which is more than enough to kill the monster, but nothing happens.