If you break the smallest of the Snow Layers in Survival with a shovel, you receive two Snowballs instead of one. This leads to a snow duplication bug. It does not happen with layers 2-8.
May have been an issue before 15w44b.
MC-91989
Breaking a single Snow Layer with a Shovel yields two Snowballs
Resolved
Duplicate
0
and dupe of MC-61821.