That is really bizarre because over level 90 we always looted the ASLYUM crafting materials.

And I do recall only looting oktal materials for a small amount of time levelling 85+ in the Ok'Tal quest line of 25, 50, 100, 150.

I do recall a change made in the drop rate of quest crystals was increased as well as elite helms for lower levels in Basin map , unsure if this affected the drop rates of the Otktal crafting materials for levels 85 to 90.

I think I might need to create a level 85 character and run the map and see because others are experiencing difficulties in getting any oktal materials at all at level 85.