Invalid argument supplied for foreach() group children

Getting the following error in Drupal 8 when displaying empty field groups in forms and displays:

Invalid argument supplied for foreach() in field_group_attach_groups

My field groups have been migrated from a Drupal 7 website with core migration tools, so there may be some inconsistency.
In any case, I think that a check for group children existence before looping in them could be necessary.