Search API Views only displaying one result I've just cloned a production site into a staging environment. I copied core and contribute, cloned the repo containing custom modules and themes, cloned the database and copied the solr configuration to a new core. Bringing up the database I configured a new search server pointing to the new core, repointed the index and reindexed the site.

All my old search API Views, and all new ones I create, only show one result. However the pager can tell that there are more. Jumping to other pages works. However no content is shown. If I do a search in solr admin I get many results.

I'm at a loss for where to start looking. As far as I can see all configuration is the same in the database and in the files. Google doesn't seem to think this is a thing. 

Is this likely to be a Views issue, a solr issue or a search API issue?

EDIT: I've called the URL directly as @Eugene suggested. It looks to me like only one result is returned by Solr. However as you can see it things that a larger number has been found.

Query string:
http://example.com:8983/solr/core2/select?fl=item_id%2Cscore&amp;start=0&amp;rows=10&amp;facet=true&amp;facet.sort=count&amp;facet.limit=10&amp;facet.mincount=1&amp;facet.missing=false&amp;facet.field=sm_field_domains%24name&amp;facet.field=im_field_regions&amp;facet.field=im_field_topics&amp;facet.field=im_field_sources&amp;facet.field=im_field_domains&amp;f.sm_field_domains%24name.facet.limit=50&amp;f.im_field_regions.facet.limit=50&amp;f.im_field_regions.facet.mincount=0&amp;f.im_field_topics.facet.limit=50&amp;f.im_field_sources.facet.limit=50&amp;f.im_field_domains.facet.limit=50&amp;f.im_field_domains.facet.mincount=0&amp;group=true&amp;group.main=true&amp;group.field=ss_field_source_url%3Aurl&amp;wt=json&amp;json.nl=map&amp;q.alt=%28ss_type%3A%22article%22%29%20%28bs_status%3A%22true%22%29%20%28index_id%3A%22solr_local%22%29%20%28hash%3Agpsxif%29

Response

  "response": {
    "numFound": 197180,
    "start": 0,
    "maxScore": 2.0000253,
    "docs": [
      {
        "item_id": "1646",
        "score": 2.0000253
      }
    ]
  },
...
}
Try to remove this from your url 

&amp;group=true&amp;group.main=true&amp;group.field=ss_field_source_url