The ?sce=view is a small snippet of code added to many of my scripts to allow the PHP source code to be remotely viewed (useful for debugging purposes and remote support).
When you try it on the index.php page with just /?sce=view, then the first script loaded that has that capability will display it's own source, and exit. In template pages, the first script with that capability loaded is likely the weather tags file (testtags.php for Weather-Display). The wx...php (and by extension the index.php page) do not have that ?sce=view capability installed, so it's no wonder you get unexpected results .. it's not a bug.. it's just the way it works.