Session Flashdata Persisting Like Normal Session Data

Hi,
I currently have an issue with Flashdata persisting and behaving like normal session data.
This occurs with direct use of Flash data like:

Code:

$session->setFlashdata('item', 'value');

As well HTTP response functions like:

Code:

return redirect()->back()->with('foo', 'message');

I am currently using PHP 8.1 and the DatabaseHandler Driver.

This has been working fine but I recently upgraded to from CI version 4.3.6 to 4.4.0.

I only just spotted this issue an assume its linked to the version change. More likely an error on my part manually changing bits as part of the upgrade or maybe missing something.

Has anyone else had any issues or can direct me to particular area of the upgrade changes I should look at more closely that might cause this issue?