Inconsistent resolution of serialized guest user reference

{{groovy}}
import org.xwiki.user.UserReference;
import org.xwiki.user.UserReferenceResolver;
import org.xwiki.user.UserReferenceSerializer;
import org.xwiki.user.GuestUserReference;
import org.xwiki.component.util.DefaultParameterizedType;
import javax.inject.Inject;
import javax.inject.Named;
import org.xwiki.model.reference.DocumentReference;

// Get UserReferenceResolver for the test
def resolverType = new DefaultParameterizedType(null, UserReferenceResolver.class, String.class);
def userReferenceResolver = services.component.getInstance(resolverType);

// Get a UserReferenceSerializer
def serializerType = new DefaultParameterizedType(null, UserReferenceSerializer.class, String.class);
def userReferenceSerializer = services.component.getInstance(serializerType);

def guestUser = GuestUserReference.INSTANCE;
println "guest user reference: " + guestUser;
  
def serializedGuest = userReferenceSerializer.serialize(guestUser);

println "Serialized guest user reference: " + serializedGuest;

// Resolved back the serialized guest user reference to UserReference
def resolvedBackReference = userReferenceResolver.resolve(serializedGuest);
println "Obtained user reference: " + resolvedBackReference;

// Check if both references are equals
def areReferenceEquals = guestUser.equals(resolvedBackReference);
println "Obtained reference is equal to the original reference: " + areReferenceEquals;
{{/groovy}}