Minecraft 1.10.2, Minecraft 16w41a, Minecraft 16w42a
Operating System: Windows 10 64-bit
Java Version: 1.8.0_101-b13
Game Mode: Survival
When you are breaking a block, and standing on top of it, when you look straight down, the breaking animation disappears.
Appears to happen most of the time, sometimes you can partially see it.
Not reproducible on transparent blocks.
Maybe the breaking animation gets drawn under the block texture?
Also affects 1.9