Postet same issue a week ago.
When i use BIS he will give me the 3 dmg Shards, but trys not to go get the Shard Set Bonus wich is very powerfull on its highest rank (when all 3 shards at rank5)
When i manually give me the set bonus and sim it, it will do 900dps more (8100 dps) compared to what Mr. Robot says is BIS (only 3 dmg Shards, no set - 7200 dps)
Furthermore will the Set procc Tooltipp refere to the lowest rank of the set Bonus wich is 300 main statt lower than the high rank set bonus (read wowhead articel about Shard Set Bonus ranks) so i assume Mr. Robot uses not the correct amount of Prime stat when Shard Set Bonus Proccs.