A player's War Chest participation level indicates how many Wars they have fought in with one Alliance. Leaving an Alliance to take part in another Alliance's War or even War matchmaking will reset this level, as players are encouraged to stay and grow together with their Alliance.
Temporarily leaving your "home" Alliance for "mercing" — i.e., participating in another Alliance's activities with no intent to stay — carries the risk of losing progress on your War Chest participation. The War matchmaking process takes about five hours. It does not start at once for all Alliances. Players are advised to not leave their Alliance until matchmaking is complete.
We cannot compensate players who have had their War Chest participation level affected due to voluntarily leaving or joining Alliances.