Duplicate post made to the bug tracker, but this way I am more confident one of you guys will see it.
Playing nightly build from 16/8/15.
Successful completion of any mission causes the retrieval of 2 bomb items from the battlefield. These bombs spawn in the dropship tiles if the RMA gives you a dropship on missions not needing bombs. As these bombs have a mass of 4kg, they will slowly and steadily fill up stores with a useless item that is not able to be sold off.
I suspect this is linked to the recent addition of mission failure/success criteria, especially as on turn 1 2 or 3 I end up with an on screen message stating "Target area unoccupied" as either my team or the alien team moves away from its initial positions.