There is a known issue in the game which has caused some players under level 12 or players who were in Spectator Mode, to be opted into the war. We have fixed the root cause of this issue, but all affected players need to login to the game or be kicked from the alliance to resolve the issue. Please note that the fix will not apply for the current war, as these wars have been already been matched.
Our apologies for any inconvenience caused by this issue. We have now been in touch with the affected alliances, who contacted us through support.