Level 72 challenges - new gear - 5 drops possible?

Delmon_Ciiidrr

So after playing the new challenges for 3 weeks, I never (!) had the new gear dropped at maximum of 5. 2 or 3 sometimes 4. Is this correct?

The drop rate of 5 gear is 0/120. That is worse than any purple gear from shards

Description error or work as intended?

Delmon_Ciiidrr

I stopped counting but 5 never dopped. Is this WAI and a descriptive bug? Or a bug in drop rate? It would be cool if this gets corrected in the near future!