Minecarts in motion will appear to be operating alongside the track, not on it.  NOT JUST VISUAL, also definitely catches on mobs, other carts, incorrect rails, and possibly some blocks.  While in motion, passes through most (but not all?) solid blocks unobstructed, will also float adjacent to the track it's allegedly on.  Also causes incorrect interactions with powered rails and detector rails; carts will sometimes not be detected, preventing redstone from correctly activating.  The glitch is currently making it extremely difficult to use Minecarts in the game outside of loaded chunks.

Expected: When spawning back into a chunk, minecarts operating via powered rails (without a player) should spawn on the rails.

What's happening: When spawning back into a chunk, minecarts operating via powered rails are spawning adjacent to the rails, not on them.

Observations: When outside of a loaded chunk, minecarts that are not correctly on the rails are:

• Catching on other carts that are correctly operating on rails.
• Catching on mobs adjacent to rails that otherwise would not impede a minecart's movement.
• Failing to be detected on detector rails, failing to activate redstone.
• Being impeded by some blocks, but not all.

To reproduce: Requires a loop of detector rails and powered rails that extends outside of a loaded chunk on opposite sides. Sending a minecart around the loop, out of the loaded chunk, will sometimes (not always!) result in a minecart spawning back into the loaded chunk off the rails. Upon exiting the loaded chunk, the minecart will fail to complete the loop, often by failing to be detected (failing to activate powered rails) or otherwise becoming stuck. When a player loads the area where the minecart has become stuck, it will appear as though it were correctly operating on the rails, but arbitrarily stopped.