We've noticed, sometimes for some reason (don't know why), after scheduled reloads in QVS (11.0.11414) the landing page assigned to some (and not always the same) documents changes.
The 'Allow session recovery' check is disabled in document's system setup, so its not due to the session interaction. When we reload the documents using desktop (and also qvs) it seems ok, but when deployed the doc to qvs and after some days (reload scheduled daily) it changes the landing page.
Until now, we assign the landing page saving the doc (after it's reload in desktop) with that sheet activated. But I'm thinking to assign the onDocumentOpen trigger to set the active sheet there, even though its not a desirable solution at all, because it won't work in ajax and our customers work in both ajax and plugin.
We didn't experienced this odd behaviour in version 10 (we've upgraded to 11 recently).
I also examined the .shared files (with sharedFileViewer) looking for corrupted sessions and I tried to find errors/info in the reload logs files with no luck.