I really wonder whether there is something account-related that causes certain people to get certain tasks more than others. You get constructs way more than I do, but I get Zhul’Kari at least once or twice a week (maybe you do, too - I don’t know).
Yesterday, I had a rare task alignment where I was able to do all 4 at once if I wanted to (4 of the same mana colour, 4 from the same kingdom, 3 from Broken Spire, 3 brown). I cleared the first one during my guild battles, but could have almost as easily done 4 at once.
For any PC/Mobile players that are interested in seeing how the task system looks in action, I took the opportunity and did a short video (about 8 minutes) demonstrating the daily task system which you can see over here: