Strongbox does not summon mobs when clicked.

I ran into this strongbox which I was able to get next too and click, but for some reason when clicking it it never actually activated to summon mobs...

Also when i ran into this thing it was unidentified and i used a scroll on it, but that was after a while of clicking it and it not summoning mobs.

Not sure if it's because it is pressed up against that wall or if its something else.

http://postimg.org/image/lr15ia7wz
http://postimg.org/image/5jfu3h237