The PHPDoc in https://we.phorge.it/source/phorge/browse/master/src/infrastructure/storage/lisk/LiskMigrationIterator.php$14 defines * @task storage.
That means the value of $task in the DivinerAtomController class is the single string storage and there is no whitespace to explode on and there is no second key in the array to set as $title.
Thus only call explode when $task contains a whitespace.
EXCEPTION: (RuntimeException) Undefined array key 1 at [<arcanist>/src/error/PhutilErrorHandler.php:273] #0 <#2> PhutilErrorHandler::handleError(integer, string, string, integer) called at [<phorge>/src/applications/diviner/controller/DivinerAtomController.php:450]
Closes T15854