@LizzBee It’s actually a little unclear to me how this works now. It used to be that if you left after matchmaking — even if you return —you were still an “Ex-Member” on the battlefield, and couldn’t use your flags.
But the new version 18 made a change to how War Chest resets work, as mentioned in the release notes.
But the release notes don’t clarify if any other changes were made to how the exit/entry for War works.
My guess is it probably works the way it used to, in which case by the time you’ve left after matchmaking happened, you’ve already created some imbalance with the other team, since your alliance will effectively have 6 fewer flags than the other one, and an extra team to clear for board resets.