$feed->processors_feed in 'update' contains empty processor entry

In my configuration with feedapi_feed_item, feedapi_feed and feedapi_aggregator installed, a feed configured as feedapi_aggregator feed returns the message

The  feed () was updated successfully.

when I update it on admin/content/feed .

I found out that $feed->processors_feed contains an entry "0" in these cases.

Array
(
    [0] => feedapi_aggregator
    [1] => 0
)

I attach a patch that prints the $feed->processors_feed property to the screen (like above).