I have been experiencing this problem for a while now and I finally got around to investigation it. I have no idea why this happens but it looks to be a bug in the Yii2 framework.
I have a session variable that gets erased as soon as I try to call the "get" method on it. I have stepped through the code in a debugger and the session variable exists right up until the time the get method is called on it. I tried troubleshooting this problem by grabbing the session variable using, $_SESSION["myVariable"] and it works. This leads me to believe there is a bug in the Yii::$app->session class. I have used the Yii::$app->session class in a-lot of areas and only experience this bug in a few.
Does anyone know why this happens and can we get this fixed please?
Thanks Hrnair, I will report this if I get a chance to dig a bit deeper. I would have posted code samples but it wouldn’t have helped. It seems to happen completely randomly on rare occasions. I have no idea why.