Snowman / Iron Golem slight into blocks(Descent altitude 0.03125, 1/32 block). It occurred in the placed Snowman / Iron Golem after a few seconds. This causes Snowman / Iron Golem the shadow disappear.
Environment
OS : Windows 10 64-bit Java 8 version : 1.8.0_65-b17 64-bit CPU : Intel(R) Core(TM) i5-4460 CPU @ 3.20GHz GPU : NVIDIA GeForce GTX 650 Drivers : GeForce 358.91
This issue has been fixed in 16w06a