I am sure some people might not see this as a bug however I don't think this is the intended behavior for whatever the drop logic is. I continue to receive Timur's Lash - and when I say continue I have gotten at least 8 of them - and it seems like it is the only legendary drop I get. Right now I have 5 of them and that is after having dismantled at least 3 in the past... as a side note although it may not be related I received drop of this weapon in Beta testing as well