A lot of players have reported poor drop rates on Master work/ Legendary Items on GM1. I am only using 1item with 35% Luck. I usually go GM2 on contracts/ strongholds but I find it a lot easier to farm on GM1. I had 1 more legendary drop the night before & I only play for roughly 3hrs a day during the week, if that.
Keep in mind that power scaling can play a factor in rewards drops as well as luck.
