If a player is in creative mode and obtains a spawner e.g. via the /give command he can place it down just fine.
However if the spawner is moved in the inventory, it disappears after being placed (the placed block and the item in the inventory).

This does only affect creative mode.
It does occur without any plugins loaded, but does not occur in Vanilla Minecraft 1.8.7.

Additional info
There are two reports suspecting that my plugin SilkSpawners is the culprit, see
https://github.com/timbru31/SilkSpawners/issues/17 and
https://github.com/timbru31/SilkSpawners/issues/19