User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-5043481-20150525113112/@comment-17735225-20150526145348

You can set the hunter for hire quest preference so that your hunters do g-rank quests at the gong in solo guild hall.

I don't think they ever request g-rank stuffs until I start setting it manually. So that might be your problem.