I made update today at Debian from 11 to 12 from SUPPORTED REPO and have similar problem:
at syslog:
Nov 18 18:50:42 hostname uwsgi[1594]: [ERROR] (grommunio Admin API) Response validation failed: [InvalidSchemaValue(value={'data': [{'pid': 1962, 'ip': '80.187.122.218', 'user': 'username@domain.com', 'start': 1700329025, 'devtype': 'SamsungDevice', 'devid': 'sec1824218997445', 'devagent': 'Android-SAMSUNG-SM-G970F/101.12', 'command': 18, 'ended': 0, 'push': True, 'asversion': '16.0', 'addinfo': 'Sink 793/880s on Calendar Tasks Contacts', 'update': 1700329819}, {'pid': 2057, 'ip': '84.159.238.187', 'user': 'username2@domain.com', 'start': 1700329790, 'devtype': 'iPhone', 'devid': 'shgl7qcm255m5379emucm9l1to', 'devagent': 'Apple-iPhone13C3/2007.81', 'command': 18, 'ended': 0, 'push': False, 'asversion': '16.1', .....
one line for A4 page, different users, different devices.
at grommunio-sync.log:
[ INFO] [username@domain.com] StateInvalidException: Invalid states found while loading collections. Forcing sync - code: 0 - file: /usr/share/grommunio-sync/lib/core/synccollections.php:127
[ INFO] [username@domain.com] StateInvalidException: Saved state are not of type SyncParameters - code: 0 - file: /usr/share/grommunio-sync/lib/core/synccollections.php:158
[ INFO] [username@domain.com] StatusException: Grommunio->ChangesSink(): Sink returned invalid notification, aborting - code: 3 - file: /usr/share/grommunio-sync/lib/grommunio/grommunio.php:1045
[ INFO] [username@domain.com] Grommunio->checkAdvisedSinkStores(): could not access advised store store 'Resource id #35' - failed with code 0x000004B9
some phones do not sync at all.