The bug
If there's an item inside the beacon (either from a hopper/hotkeys - MC-7222 or from a player currently using the beacon) you can use it. Additionally, when closing the interface, you will drop one of the items inside, if there are any.
Linked issues
is duplicated by 1
Comments 8
I tested in 15w36d and I can't seem to stop the current effect
If there's an item inside (either from a hopper/hotkeys - MC-7222 or from a player currently using the beacon) you can use it. Additionally, when closing the interface, you will drop one of the items inside, if there are any.
I'll add this to the description as well.
Can no longer confirm in 1.9

Still affects 16w05b
Can confirm for MC 1.12.1.

This allows abusive behaviour. Spectators shouldn't be able to interact with anything
Confirmed for 1.13.1.
Confirmed.