Sound glitch of minecarts

1. Some minecarts when remowed from rails keep sounding IF PUSHED by player and some don't.
How to perform bug:
1. Make construction like on first picture.
2. Place some minecarts on it (second picture)
3. Destroy the construction
4. Push minecarts around
Result: some minecarts still sound like when on rails and some don't.
I didn't figure out what exactly causes this difference.
Minecarts (that have sound) sound even when moved in th air (while falling).
When reloaded this world, none of minecarts had sound anymore.

2. (Might be related) Sometimes when you click a minecart to sit, a sound of moving minecart plays loudly for a frame of a second.