Implement a new solution: Instead of static code blocks disabling logging, rollback slf4j-api, logback-classic, and logback-core to older versions. It's the addition of the rollback for slf4j-api that seems to restore logging.

src/test/java/ca/uhn/fhir/jpa/starter/MultitenantServerR4IT.java

@@ -28,9 +28,6 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
   })
 public class MultitenantServerR4IT {
 
-	static {
-		System.setProperty("org.springframework.boot.logging.LoggingSystem", "none");
-	}
 
   private static final org.slf4j.Logger ourLog = org.slf4j.LoggerFactory.getLogger(ExampleServerDstu2IT.class);
   private IGenericClient ourClient;