[1.1.2647]Colony's shells used by hostile siege gunners

[Jan2607]

Not sure if this is a bug. I think it's really funny
I had the door of my stockpile hold open with 6 mortar shells in it, when I got sieged. I guess because of the open door, the game set my shells to forbidden and the besiegers thought it was their ammunition. The siege gunner walked all the way up, passed my colonists, waving, kindly saying "good evening, gentlemen", walked into my storage room, grabbed one shell and walked out all the way back to reload his mortar.
I love it

Now I closed the door. The gunners still are coming, knocking at the door 2 or 3 times and leaving without a shell.

https://imgur.com/FbKN2Uw