When viewing an islandora object, the title as well as breadcrumbs are being generate a second time that is handled by the title callback present in the menu callback: https://github.com/Islandora/islandora/blob/7.x/islandora.module#L140-L141.
This happens in other places within the code base as well which do not need to be handled due to the how Drupal handles inheritance through MENU_LOCAL_TASKs: https://api.drupal.org/api/drupal/modules!system!system.api.php/function/hook_menu/7.
View an object, note how the breadcrumbs and title is set.
Reduce the amount of times we are recursing through the RI needlessly.
View an object, note how the breadcrumbs and title don't change.
Any custom module calling islandora_view_object directly will cease to have their title and breadcrumbs set such as compound: https://github.com/Islandora/islandora_solution_pack_compound/blob/7.x/islandora_compound_object.module#L255.
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