Hoping someone would reply to don2020 since I just got the same problem as well. I requested leave from Tachibana's army and in the middle of my first week away, the notifications went crazy with "With your commander's defeat, you have been released from service." and I didn't get a notification while on the run ever since.
Checking the 'recent messages' (or something), it was just filled with the same phrase.
Though I have a backup save not too far back from the incident, it'd be nice if someone could find a solution to this