The current Solr config is exported and loaded in Solr.
Indexing from Drupal works.
The Solr Index View shows the correct number of results in the header, but shows the "no results" content.
Looking in the logs I see:
Drupal\search_api\SearchApiException: The datasource with ID 'lhltl6--entity:node' could not be retrieved for index 'Solr index'. in Drupal\search_api\Entity\Index->getDatasource() (line 369 of web/modules/contrib/search_api/src/Entity/Index.php).
If I look at the indexed data in Solr the IDs look like this:
When the solr ID is created, the name of the index seems to be added to the ID. But when the document is read in the view, the index ID would seem to be missing.
The View seems to be querying the correct rows, but is trying to retrieve the documents with an incorrect ID.