whenever I try to ride my minecart system, I have to get off every 16 chunks to load the next portion of the track. (it also makes the "On a Rail" achievement impossible to obtain). I have discovered this bug is also present when I ride my horse or pig. I have not yet tried boats, but they might also be bugged in the same way.

Steps to reproduce: Ride a horse, pig or minecart 64-528 blocks away(depending on your render distance) and the chunks you reach should be unloaded and remain unloaded until you get off.