Random is not bypassing heroic lockouts - FAIL
Contrary to what blizzard blue postings state, the random heroic instance feature is not bypassing heroic instance lockouts. If you've already done a heroic for the day, and you later get a random heroic for that instance, you are screwed. The bosses will be non-existent.
I'm hoping this is an isolated glitch, or else a known bug, and is not now intended to be the way things work.
I did heroic Nexus earlier, and just now got Nexus as the random heroic. I ported in, cleared trash to Omorok, only to discover Omorok was MIA, backtracked and Keristraza MIA also.
Dungeon Finder definitely does not bypass instance locks
Ok, I used Dungeon Finder exclusively last night for heroics.
I got Anh'Khet, Violet Hold, CoS, Gundrak, Nexus, all completed. Then I Violet Hold again. With Violet Hold the second time, entering showed that it was spent, no event starter NPC, no instance reset, no instance lock bypass. The extra 10 emblems from the first five were great, but I certainly was hoping what blue posts said about DF bypassing instance locks. Now every time I get a repeat instance I have to wait for the DF deserter debuff to expire before trying again, and the odds of course get worse on repeats as more are completed.