field groups inside field collections not rendered in node (edit form).

i have raised this as an issue on field collection also: https://www.drupal.org/node/2670354

summary of 2670354:

if i embed fields within a fieldgroup inside a field collection, all the fields contained within the group are hidden in the node which contains the field collection. if i move them out of the group they appear.

compare:

node
-- field collection (contains)
   [field-group
     --field (hidden in node form)
     --field (hidden)
     --field (hidden)
  ]

with

node
-- field collection (contains)
     --field (visible)
     --field (visible)
     --field (visible)
     --[field-group] (redundant).