When migrating a session the login screen displays.
This is what happens when a session is transferred:
The cookies are read from the original visitor browser.
They are copied to the Universal Co-Browsing shared browser.
The page is loaded into the shared browser.
This means that, for the user, it looks like a page reload and technically, except for the change of the browser, it is similar to a refresh of the browser. Under most circumstances this is not a problem. However, you must be aware of how this can affect the session.
For example, if your system goes to the login screen on refresh then the user will be presented with a login screen at the start of the session (as starting a co-browsing session is similar to a refresh).
If the application itself is moving to the login screen after a refresh, then there is nothing that we can do.
This issue can only be solved by modifying your browser behavior.
Unblu cannot, nor should it, modify the core functionality of your web site. The application must be updated to be capable of handling page refreshes / reloads.