Most of the objectives are based on a "steps" counter. When using Tier I & Tier II maps there is a very slim chance to get all the objective to spawn. Hack the Horde being a great example.
My only other thought would be, if you are seeking an objective, try to use a map that the req. level is equal to the level needed to unlock the objective.
Example - Lv 6 unlocks Pinch of Evil - I would run a level 5 map at minimum ( I have spawned the quest on a Tier III map before with EP Mods, but normally at the end of the map)
Example - Lv 10 unlocked Hack the Horde - Again I would at minimum run a Lv 10 Map (but I have spawned the quest on a Level 5 map close to the end)
Or you can level to 10, have Pinch, Bits n Pieces and Hack the Horde open and run a lv 10 map and hope you get all 3
