Furnace minecarts no longer couple up together with minecarts

When trying to connect Furnace Minecarts with Minecarts, they do not pull each other. This link shows how they are supposed to behave: https://youtu.be/V1tBzuMcCpc?si=52uUtRrpLSrbRuwg

How to reproduce:

1. Place a line of rails with a solid block on one side.
2. Place a furnace minecart on the rail.
3. Place a regular minecart behind the furnace minecart, so that it's closer to the solid block.
4. Push both minecarts towards the block so that the two minecarts are as close to each other as possible.
5. While looking at the opposite direction, power the furnace minecart using coal or charcoal.

Expected result:

The furnace minecart would pull the other minecart along with it.

Observed result:

The furnace minecart stops pulling the other minecart after moving a few blocks away.