Hey there for the last week I have been complaning (along with a lot of other people) that sparks were not there after Lilith, ubers or even iron wolves cache. Yesterday I finally had 3 sparks when I got to alchemist (Lilith, cache and Varshan) but I went for Duriel for the first time and did not get the spark again. At this point I think there is a delay of sparks showing up maybe?
I will be watching my spark count and update this while hopefully Bliz can look at it from this perspective as well.