[eluser]Vheissu[/eluser]
Hmm. So it is storing and value and keeping it, it would seem. Because if the issue was happening still, then the value you just set would have said "Empty session, setting a test variable"
I'm starting to think the issue might be related to using the session class within a custom library. If it works in a controller, but not your auth library class (like it is happening for me), then we've just isolated when the issue is happening somewhat.
Now the question is: why isn't the session class working in a custom library properly?