Ctools calls hook_block_view_alter with incorrect paramaters ($data should be an array, not an object)

hook_block_view_alter accepts 2 arguments:

$data: An array of data, as returned from the hook_block_view() implementation of the module that defined the block:

$block: The block object, as loaded from the database, having the main properties:

However, in some cases ctools calls this function with 2 objects, instead of an array and an object. I believe this is the cause of the WSOD issue described at #1586876: Not compatible with Login block in Panels (anonymous see white screen). It manifests itself if you have modules that implement hook_block_view_alter and you try to put the user login block into a panel pane, and then view it as an anonymous user.

If hook_block_view_alter is to be called, then it needs to be done so with the correct paramaters.