The Android browsers, all of which use the WebKit library, fail to send Authorization info on every AJAX request, then when the server responds Login Required, the AJAX request is sent again, this time with the Authorization info.
ACP, when it receives a request without login info, kills the current session. The effect is, then, that the session for the user is lost. You can see this by the Owner field in the System Status display changing to Free within a few seconds of the run starting (when the first AJAX update occurs).
Possible solution is to avoid killing the session on a request that fails authentication. Let it sit out there until replaced. This will require the existing logic for jumping on to an old session to work!