It's correct if you don't complete the triumphs that gives you a boost because mine didn't drop until I had the 5 boost.. I got it to drop the second week of the dungeon. First week I only did did it on one character and then the following week I did it on all 3 I got it to drop on my third character.

During D1 my friend ran CE 3 times a week every week from the time TDB released until D2 released, so almost 3 yrs, he never did get the crux of crota he was trying to get. He hasn’t played since. I tried to tell him Necrochasm wasn’t worth the effort he was putting into it, he wouldn’t listen.

It's intentional, only [i]legacy[/i] raid and dungeons had their exotic lockout removed. Equilibrium, as its not a legacy dungeon, will not be farmable for the exotic until another dungeon launches or unless Bungie decide to make it a legacy dungeon earlier than that. [quote]General Removed weekly lockout on Exotic weapon rewards in legacy raid and dungeon activities. These now have a chance to drop each time their source encounter is completed.[/quote]https://www.bungie.net/7/en/News/Article/destiny_update_9_1_0_2