blendmodes do not save from ofCairoRenderer?

The blend modes look good on screen but is not saved to PDF or SVG.

//--------------------------------------------------------------
void ofApp::draw(){
	ofBackground(ofColor(255,255,255));

	if (saveVector) {
		ofBeginSaveScreenAsPDF("blendMode_test.pdf", false);
	}

	ofEnableBlendMode(OF_BLENDMODE_MULTIPLY);
	ofSetColor(ofColor(80,40,255));
	ofDrawRectangle(0,0,100,100);
	ofDrawRectangle(50, 50, 100, 100);

	if (saveVector) {
		ofEndSaveScreenAsPDF();
		saveVector = false;
	}
}

//--------------------------------------------------------------
void ofApp::keyPressed(int key){
	if (key == OF_KEY_DOWN) {
		saveVector = true;
	}
}

Start by reproducing the supplied example with ofCairoRenderer and the ofBeginSaveScreenAsPDF/ofEndSaveScreenAsPDF entry points, comparing the on-screen result with the generated PDF and SVG. Done means OF_BLENDMODE_MULTIPLY is preserved in both vector outputs, matching the screen rendering.