Minecarts are reversing instead of turning at a specific turning rail corner. At a corner where the cart should turn from west to north, it goes back east. Said corner is temporarily turned as part of an intersection involving redstone. It only seems to happen if the cart is going at a specific speed. If the rail is continuously unpowered or a player is in the cart, it also turns like normal.

I can't reproduce, even when making a similar railway junction. I can provide a longer video (too big to fit here) or the save itself as needed.