ofFbo: broken on Android

Following code shouldn't draw anything because I don't call fbo.draw()
But I get a red screen with a green square at the bottom (y coord is inverted)

ofFbo fbo;

//--------------------------------------------------------------
void ofApp::setup(){
    fbo.allocate(600, 400);
}

//--------------------------------------------------------------
void ofApp::draw(){
    fbo.begin();
    ofClear(125,0,0);
    ofSetColor(0,255,0);
    ofFill();
    ofDrawRectangle(10, 10, 100, 100);
    fbo.end();
}

Reproduce the minimal example on Android, starting with the ofApp setup() and draw() flow and the ofFbo allocate(), begin(), and end() calls shown. Confirm that omitting fbo.draw() produces no visible output and that the rectangle does not appear with an inverted y coordinate.