I am having the same issue and have found that the problem is related to either cookies or session variables. Not sure which one yet. You will most likely find that you can make the problem go away by doing the following. This will not resolve the issue, just help to better identify the problem.
If you change the URL of the Secure and also the Unsecure to match (http and http) or (https and https) It will most likely start working. (SEE ATTACHMENT)
I realize that this is not the resolution that we are looking for but this is what I have determined where the issue lies.
I have tried clearing caches, disabling caching and everything else under the sun and this is the only thing that has worked so far. It is a session variable issue that is not passed from the unsecure cookie to the secure cookie I believe - could be wrong here. I don’t yet have a clear understanding of how this part is being implemented.
Maybe someone can elaborate and fill in the blank for us.
If I had hair, I would have pulled it all out by now :o) Lucky for me.
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