Guild Wars 2

so i did the jumping puzzle
an i opened the chest

(this is like my third time clearing it or fourth)

and i got NOTHING

someone want to explain this to me

first few times i got somethin
but i thought it was a farmmable chest isnt it

let me know if im wrong

Today i farmed this chest like crazy and each contain 3 giant gift box. But now it seems not contain anything…