xsi:schemaLocation does not work for schemas in user catalog

[weberjn]

I added a schema to the XML Catalog - User

but validation of an xml still fails with

schema_reference.4: Failed to read schema document 'file:///C:/gitprojects/camt/camt.054.001.02.xsd', because 1) could not find the document; 2) the document could not be read; 3)
the root element of the document is not xsd:schema.

The schema is fine, I can open it in the schema editor.

Eclipse EE
Version: 2024-09 (4.33.0)
Build id: 20240905-0614