As I walk around the chunks unload behind me, and I can see it for a full second until I walk past it. It only happens while sprinting and when I am in F5, thirdperson, mode. My video settings are included.
Environment
Java 1.7.0_55 64bit, 4gb allocated ram, GeForce gt 525m/PCIe/SSE2, Intel(R) Core(TM) i7 2620M CPU @ 2.70GHz
This happens to me as well, though even without thrid person view, it happens if I have a high enough FOV (I play with 90) and am looking diagnally.
EDIT: It also happens when you change FOV, though this is probably to be expectated.
14w30b - Windows 7 - Java 7