Direction of toggleable furnace minecarts doesn't seem to be saved properly

[skymen]

When a furnace minecart is toggled off by an unpowered rail, saving and quitting doesn't seem to save the moving direction properly.

https://youtu.be/ncOmZyC4E94

Tried my best to find the root cause of this issue, but it seems to be a behavior attached to Minecraft's getMovementDirection function which seems broken in this specific case.
I tried a few times, and it does not seem to be related to chunk borders, and it doesn't seem to be particularly attached to any given axis. In fact, I don't even know if the behavior is consistent.

Perhaps a fix would be store the pushX and pushZ as additional NBT data before toggling off the cart in case it gets saved/loaded.