Spawner spawns entities with NBT tags and monster with no Pos tag at wrong position
The bug
Spawners do not spawn entities at the correct position anymore or do not spawn them at all, which might be caused by the fix of MC-90101
Entities with NBT tags
Spawners spawn any entity that has NBT tags other than id but no Pos tag at (0|0|z). This means only their z-coordinate is used.
Monsters
Monsters with no other NBT tags than id an no Pos tag are spawned at (0|y|z). This means only their y- and z-coordinate is used.
How to reproduce
Use the following command
/setblock ~ ~1 ~ mob_spawner 0 replace {SpawnData:{id:"ArmorStand",NoGravity:1b}}