Valid delete SPARQL results in server error

This SPARQL properly deletes the intended triples (Community v5.2.0)

DELETE { ?p ?o. }
WHERE { OPTIONAL { ?p ?o. } }

The same SPARQL against a deployed cluster (v5.2.3) results in a 500 internal server error.

Can you provide any errors that would have printed in stardog.log upon the 500 internal server error?

I sent you the log file.