Originally Posted by LZS

my advice, just run ur event, until it pops raid bosses. then let the raid bosses be, and you go for hunting SG.
I do that too, i run 10 or 20 stam event mission and when the raid boss pops, i let it be while i went farming SG on normal mission.

Well actually, when you have a raid boss available, your chances of getting a bonus stage are the same, when the game decides to give you a raid boss but its not available it will give you nothing.

Also if you have an expired bonus stage for whatever reason this will cause that you won't get any more bonus stages of the same difficulty until you refresh the page.