Any mob_spawners being placed with /give will spawn the right mob for only the first time, after that it turn into a PIG spawner. mob spawners placed with /setblock command will just be a pig spawner. I am 99.99% sure I have used the right command.

I have tried commands like...

/setblock ~ ~ ~ minecraft:mob_spawner 0 replace {EntityId:Skeleton}
/setblock ~ ~ ~ minecraft:mob_spawner 0 replace {BlockEntityTag:{SpawnData:{id:Zombie}}}

/give @p minecraft:mob_spawner 1 0 {BlockEntityTag:{SpawnData:{id:Zombie}}}
/give @p minecraft:mob_spawner 1 0 {EntityId:Zombie}

They have created ERRORs

However, I have tried to use

/setblock ~ ~ ~ minecraft:mob_spawner 0 replace {SpawnData:{id:Zombie}}

it seems to work for a while, but when I exit and re-enter the world, its a PIG spawner!

Please Help!!

P.S. Happy Easter!!!