Kerbal Space Program

To reproduce, create simple craft with 8 unit array of decouplers and launch. As shown in photos...
1. Open up the icon stack in the staging area and place cursor over item 1 to note its location on the ship.
2. Place cursor on item 8 to note the last item in the array on the ship
3. Collapse the icon stack in the staging area by clicking on each item once (this really needs a better way too, like right clicking or something)
4. Select the 8th item on the ship itself and manually click the decouple button.

RESULT, as shown in #4 is the staging area shows an empty stage where the other decouplers should still appear. Only way to restore is to go to tracking station and return, or reload from quick save.

Tested with no mods or DLC installed yet.