Solr indexing problem when linking dataverses containing "Geographic Bounding Box" metadata

Bug description

When creating a link between two dataverses via the API, if the source dataverse contains a dataset with geographic coordinate metadata (bounding box), a Solr indexing error occurs.

Steps to reproduce

1. Create Dataverse A containing a dataset (draft or publish) with geographic coordinate metadata (bounding box)
2. Create Dataverse B which will host the link
3. Execute the API command to create the link:

curl -H "X-Dataverse-key: $API_TOKEN" -X PUT "http://$SERVER/api/dataverses/$linked-dataverse-alias/link/$linking-dataverse-alias"

Observed behavior

Dataverse v6.0

The API returns an error directly (also present in the SolR logs):

{"status":"ERROR","message":"Command edu.harvard.iq.dataverse.engine.command.impl.DeleteDataverseLinkingDataverseCommand@499c5c52 failed: Exception thrown from bean: jakarta.ejb.EJBTransactionRolledbackException: Exception thrown from bean: org.apache.solr.client.solrj.impl.BaseHttpSolrClient$RemoteSolrException: Error from server at http://localhost:8983/solr/collection1: Exception writing document id dataset_8 to the index; possible analysis error: DocValuesField \"boundingBox__maxY\" appears more than once in this document (only one value is allowed per field)"}

Dataverse v6.8

The API does not return an error (apparent success), but the same error appears in the Solr logs:

Exception writing document id dataset_8 to the index; possible analysis error: DocValuesField "boundingBox__maxY" appears more than once in this document (only one value is allowed per field)

Result

In both versions, the dataset from Dataverse A is not visible in Dataverse B (link host).

Expected behavior

• The link should be created without errors
• The dataset with geographic coordinates should be visible and searchable from the host Dataverse

Tested versions

• Dataverse 6.0
• Dataverse 6.8

Are you thinking about creating a pull request for this issue?

No fix is currently planned by the team.

Start by reproducing the failure with the dataverse link API command and a dataset containing Geographic Bounding Box metadata, then inspect the link-creation and indexing path around the reported Solr error. Done means the link succeeds without the duplicate boundingBox__maxY error and the dataset is visible and searchable from the host Dataverse.