I got the same message but complaining about 5 error messages. 
It will put a lot of pressure on the developers to quickly fix the error messages that arise due to bugs, as a red warning that starts at 1, so to speak, is very upsetting and will also cause a lot of threads here in the forum.
I updated two servers
one with MariaDB: the logging tab no longer shows anything and remains empty
one with PostgreSQL: logging tab works.
Both servers log much errors like this:
{
"reqId": "OxYWvtlFe20FlNldOf6C",
"level": 3,
"time": "2023-11-10T20:58:49+00:00",
"remoteAddr": "192.168.188.36",
"user": "admin",
"app": "core",
"method": "GET",
"url": "/cron.php",
"message": "Could not decrypt or decode encrypted session data",
"userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36 OPR/104.0.0.0",
"version": "28.0.0.4",
"exception": {
"Exception": "Exception",
"Message": "Authenticated ciphertext could not be decoded.",
"Code": 0,
"Trace": [
{
"file": "/var/www/nextcloud/lib/private/Security/Crypto.php",
"line": 119,
"function": "decryptWithoutSecret",
"class": "OC\\Security\\Crypto",
"type": "->",
"args": [
"*** sensitive parameters replaced ***"
]
},
{
"file": "/var/www/nextcloud/lib/private/Session/CryptoSessionData.php",
"line": 85,
"function": "decrypt",
"class": "OC\\Security\\Crypto",
"type": "->",
"args": [
"*** sensitive parameters replaced ***"
]
},
{
"file": "/var/www/nextcloud/lib/private/Session/CryptoSessionData.php",
"line": 66,
"function": "initializeSession",
"class": "OC\\Session\\CryptoSessionData",
"type": "->"
},
{
"file": "/var/www/nextcloud/lib/private/Session/CryptoWrapper.php",
"line": 112,
"function": "__construct",
"class": "OC\\Session\\CryptoSessionData",
"type": "->"
},
{
"file": "/var/www/nextcloud/cron.php",
"line": 62,
"function": "wrapSession",
"class": "OC\\Session\\CryptoWrapper",
"type": "->"
}
],
"File": "/var/www/nextcloud/lib/private/Security/Crypto.php",
"Line": 135,
"message": "Could not decrypt or decode encrypted session data",
"exception": {},
"CustomMessage": "Could not decrypt or decode encrypted session data"
}
}
Does that have somethng to do with my self signed certificates?
Lots of other errors as well but need more time to monitor.
Good:
groupfolders-app comes with an update (16.0.0) for Version 28 and works!
Much luck,
ernolf