Return of Reckoning

Last night with Destro siegeing Altdorf my 24 man was attacking a cannon and it's health was going up and down like it was being healed. So, I ask, during a city siege can cannons be healed while they are being attacked? Would appreciate an answer from a GM or any staff member please.

I had a similar observation recently with "Fury of the Green" - the NPC in step 2 was "passively" healed because my defensive target fought around it in a 20m radius. A nice but surely unintended side effect. Whether this works with cannons ... no idea. But possibly possible.