Anyone else having issue with the Mk3 Carbanti drop rates?

I can't tell if this is a bug or incredibly poor luck but I don't believe I have ever once, in all my years of playing, gotten more than 5 Mk 3 Carbanti sensors from a single weekly challenge. I actually thought the max you could get in one go was 6, but checking the spelling for this post I realized it was 7.

That was shocking. Either the drop rate is insanely low for 6 and 7 or there's a software issue. Anyone else have any insight. Your input would be appreciated.