If an empty minecart is pushed into a minecart containing an entity so that they link up they will travel until the rail bends or another entity on the rail blocks them.
A video of the problem can be found at https://www.reddit.com/r/Minecraft/comments/l5xyr0/who_needs_powered_rails/
Expected Result
They would eventually slow and stop not continue moving
Attachments
Comments 3
Can confirm in 1.17.1. This should also be related to MC-14.
Relates to MC-142045