When getting a custom mobspawner with /i 52:50 1 or /give player 52:50 1 (should be creeper spawner), you get a custom spawner, however when using /i 52:50 1 lore:Test it still works, /give player 52:50 1 lore:Test does not work and gives you a default mobspawner.

This has been discussed here #22

This looks fixed with 106.

And working, too, thanks.
Any idea about the permissions?

File as another bug please