Critical error Shield session info

Can someone help me better understand what is happening here? This is triggering the "Whoops....." page on production site. The whole site uses authentication with Shield. Here is the error log details:

CRITICAL - 2023-02-15 19:26:41 --> The user has User Info in Session, so already logged in or in pending login state. If a logged in user logs in again with other account, the session data of the previous user will be used as the new user. Fix your code to prevent users from logging in without logging out or delete the session data. user_id: 123456
in VENDORPATH/codeigniter4/shield/src/Authentication/Authenticators/Session.php on line 628.
1 VENDORPATH/codeigniter4/shield/src/Authentication/Authenticators/Session.php(161): CodeIgniter\Shield\Authentication\Authenticators\Session->startLogin(Object(CodeIgniter\Shield\Entities\User))
2 VENDORPATH/codeigniter4/shield/src/Controllers/LoginController.php(62): CodeIgniter\Shield\Authentication\Authenticators\Session->attempt([...])
3 SYSTEMPATH/CodeIgniter.php(925): CodeIgniter\Shield\Controllers\LoginController->loginAction()
4 SYSTEMPATH/CodeIgniter.php(480): CodeIgniter\CodeIgniter->runController(Object(CodeIgniter\Shield\Controllers\LoginController))
5 SYSTEMPATH/CodeIgniter.php(349): CodeIgniter\CodeIgniter->handleRequest(null, Object(Config\Cache), false)
6 FCPATH/index.php(67): CodeIgniter\CodeIgniter->run()

I know it says: "Fix your code to prevent users from logging in without logging out or delete the session data."
But, I don't know how that is happening. The site has a few pages that are accessible by all - but the authenticated section is only accessed through the login form - unless the user is logged in. I am using 'remember me' option. Also, filters on all the internal pages. So, a user shouldn't even see the login form unless they were logged out.
I'd appreciate any insight. Thanks