Hopper in a minecart despawning

When i do redstone and use a hopper in a minecart it despawns when i don't let it move each time it happens i get anoyed so i have to place it down again later it disappers and i have to place it down so it is very anoying so mojang needs to fix it qiuck other wise other redstone

builds that have it will despawn

 

by charles jiang