@sonnb
I had a look at this this morning and the issue arises when the Gallery Index (sonnbXG_loadedContent) is set to a feature that is disabled. For instance when the Category feature is disabled and gallery index is set to category list, the index action of the main controller will reroute to the category controller. The category controller's preDispatch methed then checks to ensure that categories are enabled and if they are not throws a response exception with a redirect to the gallery index. The gallery index controller then attempts to reRoute back to Category and so on...
In order to fail gracefully I think it would be best when you are switching on $loadedContent to ensure the feature is enabled before and breaking if it isn't before dealing with the reRoute. This would of course result in the default main albums index being displayed, saving users from errors when administrators set bad values for the options. A quick update of the helptext for the loadedContent option in the admincp would encourage people to check they enabled the right features for their selection.