search_api_solr_views_data_alter() not always returning all virtual fields

On my installation I came across a bug which resulted in the virtual field "search_api_viewed" not always being displayed within Views. It often, but not always, reported a "Broken handler" error message within the Views interface.

The bug dissapeared when I removed the "Default node index". This is automatically created upon installing search_api, and was not configured. Looking through the code, whenever search_api_solr_views_data_alter() comes across an index for which ->server() returns NULL, it breaks out of the function ("return;") and other indexes are not processed. According to me "return;" should be "continue;". Bug hasn't occured ever since.

Patch attached.