Guild Wars 2

Question to those who tried tribulation mode few time for many skins:
Did you get your Z-3 item after last boss fight?

I tried to defeat King Toad second time for my second green-y weapon and… I didn’t get the reward. I did get Z-1 and Z-2 from previous zones.

Is it normal? Maybe there is some kind of a timer?

The drops from the chest are once a day.