So this bug was found out by me walking in a multiplayer world on the snapshot then soon when I broke a block under a Lilac it dropped 2 Lilacs. When I kept testing it out it got me tons of flowers and it works with any two tall flowers and also the two high grass. The way to duplicate them is just plant them on dirt break the dirt and two comes out.
MC-62758
Tall flowers drop two items when block below is broken
Resolved
Fixed
7
Confirmed
Minecraft 14w29b, Minecraft 14w33c, Minecraft 1.8-pre3, Minecraft 1.8
Minecraft 1.8.1-pre1
Retrieved
Confirmed