The TileStateChanged event is raised when an RadTileViewItem changes its TileState and this is not bound to its loading. As for the loading, could you please give us some code snippets or a project to show us how exactly you're loading your items and how you're switching between Tile A and Tile B?
I've attached a sample project in which I show some of the ways to handle the loading of an items so you can examine it and see if it helps you.
the Telerik team
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