Add related field node limit I am using drupal search api with facet api modules.

I am trying to add more than 3 related node in my search index, but I am limited to max 3 nodes.

I have articles, styles, brands, designers, themes content nodes. 
I created a search index on articles on the fields page; after adding 3 nodes, the  fourth node doesn't show. The reason I am doing this is to have title of nodes as facets.

I was able to add 4 related nodes on another machine. Is there any limitation to the number of related nodes that can attached to the index?
I found a solution instead of related nodes. I am using default node field attached with articles and have cache mapping of other content types with titles and id. And implemented custom code segment encoding which replaces id with title from mapping.