Well, if that's the case, then I'm curious as to why I was shown 12201 near the end of completing the Citadel DLC, and once complete it dropped to 7926. I turned on the game again a few hours later to copy over the War Assets for the 7926 amount, and it displayed 12201, yet again. Therefore, I was only able to copy the war assets from there.
The amount of assets had also fluctuated during my entire playthrough. For example, I would have acquired just over 7000 War Assets after saving the Turians and Krogan, and then it would drop to around 3.5k. Then, it would increase to over 9k (no pun intended) after saving the Quarians, but then drop again to around 4-5k. This happened at least 4 times during my playthrough, and eventually left me at 12201 before completing Cerberus Headquarters. I will assume that the 7926 Asset rating that was shown beforehand is the actual amount. Still, though, it's more than the normal amount.
the game will still register them, but it won't show up until you reset the galaxy of war map. In your case, by restarting the game, but more simply done by clicking on the galaxy of war tab on the war assets console.
no, you have the 12000whatever war assets, the game just tells you that you have less when your galaxy at war map changes. the bug happens when the % goes down, even when you are at 50% it keeps going down at regular intervals which Is capped at 50%.