Drop rate of shield for Weapon atk 60% and other scrolls

Today, I have been hunting at Ninja Castle Hallway at the map with Chunin and Kunochi at Ch1 for around two hours and Ch2 for more than one and half hours. I got four gachapon tickets, around 1,000 cash vote coupons, 14 equipment, 2 wolbi throwing stars etc etc. but not a single scroll at all from both monsters. It is really weird, as I used to get various scrolls from them there within a hour or so.

Please check and balance the drop rate.

Thank you.

 

When it first launched, I remembered, I did get 10% and 70% scrolls and even the 60% shield atk from them but not until lately. Right, Shield atk is hard to get, but not even a single, common scroll, strange !!!

Its just the RNG, ???