Minecarts do not move across rails that run from the south turning into either the east or west. They will stop completely at one that runs from the north turning into the west.

What I expected to happen:

The minecart to take the turn and continue along the rail.

What actually happened:

When coming from the south and going either east or west, they would "bounce" back and away from the turned rail back towards the south. When coming from the north and going west, it would stop right on top of the turned rail.

How to reproduce it:

1. Place a rail running from the south and towards the east or west and one running from the north and towards the west.
2. Place a minecart on either end of each rail
3. Send the minecart down the track