update-fields.sh for updating solr schema adds all possible fields

What steps does it take to reproduce the issue?
Create a new metadatablock and add it to the dataverse asdescribed on the docs: https://guides.dataverse.org/en/latest/admin/metadatacustomization.html

After downloading the generated fields with http://localhost:8080/api/admin/index/solr/schema run the update-fields.sh script

calling curl "http://localhost:8983/solr/admin/cores?action=RELOAD&core=collection1"
fails, because seemingly all fields are duplicated

• When does this issue occur?

calling curl "http://localhost:8983/solr/admin/cores?action=RELOAD&core=collection1"

• Which page(s) does it occurs on?
  admin api

• What happens?
  calling curl "http://localhost:8983/solr/admin/cores?action=RELOAD&core=collection1"
  throws an error with java stack pointing out that the very first (and probably all) field is duplicate

• To whom does it occur (all users, curators, superusers)?

• What did you expect to happen?
  status 0 response

Which version of Dataverse are you using?
The Dataverse Project v. 5.12.1 build 1122-cf90431

Start with update-fields.sh and reproduce the workflow through the admin API endpoint http://localhost:8080/api/admin/index/solr/schema. Reload the collection with the documented curl command and inspect the Java error; done means the generated fields are not duplicated and the reload returns status 0.