hollow notch
I play on mobile, quickly double tapping any mission when it says "mission complete" allows you to start it again right away. That also includes discount missions, which allows for x11 discount missions to be started. I don't know what happens once it ends because it's 52 hours. The trick is fairly difficult and can be inconsistent, but after a few tries it should be doable.
mighty ibex
That's intented probably bcz rank 10 means discount = rank + 1 as far i know
elfin hollow
That's intented probably bcz rank 10 means discount = rank + 1 as far i know
The bug is that that rank shouldn't be achievable
