I have been farming HQ mats for all my crafting quests (currently on the lv 45 ones), and I have noticed some extreme streaks of drops and no drops. Same with HQ mats. Its just random.
Killed 25+ Toads with not a single drop, HQ or NQ. Went 1/2 on HQ Eft Tail. 85 Peiste skins until I got 2 HQ to drop.
Just at the mercy of the RNG. Good luck on your farming~!