These being complete RNG is going to really suck for the unlucky people. 0 shards from raid so far.
I want this for M+ too that would be cool
After killing the first 4 SoD raid bosses on heroic difficulty, I went into LFR and got a shard off the third boss...my 2nd kill of the boss on two difficulties. So shards CAN drop on the subsequent kills of a boss on different difficulties. I think it might be more likely that once you get a shard from a particular boss, then it might not drop any more that week. More experimentation is needed.
Yeah some people want to get gear, do progression and move on with their life haha