After trying to add new field collection item, I get this message in Chrome when going back to the previous page in browser: Notice: Undefined offset: 92 in field_collection_field_widget_embed_validate() (line 1675 of /sites/all/modules/field_collection/field_collection.module). and when I tried to save I got this:

EntityMalformedException: Missing bundle property on entity of type field_collection_item. in entity_extract_ids() (line 7734 of /includes/common.inc).

I should add that I'm having 92 items in my field collection. When I work in Firefox the browser just freeze. Can't find any other solution to my site at the moment then to use field collections this way. Any thoughts? I wonder if a field collection inside a field collection would decrease the heavy JavaScript load?