Seafile CE 11.0.13 to 12.0.11 Upgrade "Cannot find JWT_PRIVATE_KEY value from environment"

I am trying to upgrade a Seafile CE server v.11.0.13 to v.12.0.11 running on Ubuntu 24.04 using the standard binaries. Following instructions in the Manual, including the Clean Database notes, the upgrade completes without an error.

When Seafile is started, however, the following error is reported on screen:

Cannot find JWT_PRIVATE_KEY value from environment, try to read .env file.
[seaf-server] is running, pid 1136. You can stop it by: 

        kill 1136

Stop it and try again.

Killing the pid and retrying results in the same error message. Rebooting does not help.

The .env file is prepared and saved to /config/.env as described in the Manual for binary installations. It includes a JWT_PRIVATE_KEY generated by pwgen as described in the same section of the Manual.

SDOC is not running and Notification server has not been upgraded. OnlyOffice is running (Docker) from the previous installation. Nginx is also running from the previous version of Seafile.

Does anyone have any suggestions on how to fix this?

-Thank you

This is not an error but an information.

Here is the messages on a working Seafile instance:

What make you think your Seafile instance does not work?