URL parameters continue to be removed

We use a third-party application on our web site that enables users to ask questions and view on-demand videos & demos on our site. Some of the content is locked and requires registration. Once registered, the user will receive a custom link with parameters that unlocks the content so they can view all videos. We’ve now found that the parameters continue to be removed when clicking on the link so the content remains locked. For example, after I registered, I received the following link: https://greenlightcorp.com/demos/?p=5d2033fcec46bec53aa52cc93605686f. But when I click on it or copy and paste the link, the parameters quickly disappear so that I land on https://greenlightcorp.com/demos/ and the content is still locked. I tested disabling our plug-ins but that didn’t change the issue. Any idea what could be causing this?

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