Reproduction steps:
1. Open the attached project (Repro.zip)
2. Open scene "New Scene"
3. Play
4. Using arrow keys rotate the object and notice that some parts are not rendered when moving up or down

Expected behavior: Objects parts should not disappear unexpectedly when it still should be visible.

Actual behavior: Some parts of the object are no longer rendered when camera rotated in the X axis.

Workaround: Checking "Update when offscreen" on the disappearing objects "Skinned Mesh Renderer" component fixes the problem.

reproduced on: 5.4.0b10, 5.3.4f1, 5.2.4f1, 5.1.4f1