ofFbo android render

when i use a fbo on android without fbo.draw()
do i still get the fbo render.

a simple example of code to reproduce the problem:

/* ofApp.h */
#pragma once

#include "ofMain.h"
#include "ofxAndroid.h"

class ofApp : public ofxAndroidApp{
	
	public:		
	void setup();
	void update();
	void draw();
	ofFbo fbo;
        ofTexture tex;
        ofImage img;
};

/* ofApp.cpp */
#include "ofApp.h"

void ofApp::setup()
{
    img.load("img.jpg");
    fbo.allocate(img.getWidth(),img.getHeight());
}

//--------------------------------------------------------------
void ofApp::update()
{
    fbo.begin();
        img.draw(0,0);
    fbo.end();
}

//--------------------------------------------------------------
void ofApp::draw()
{

}

/* main.cpp */
#include "ofMain.h"
#include "ofApp.h"

int main(){
	ofSetupOpenGL(1024,768, OF_WINDOW);			// <-------- setup the GL context

	// this kicks off the running of my app
	// can be OF_WINDOW or OF_FULLSCREEN
	// pass in width and height too:
	ofRunApp( new ofApp() );
	return 0;
}


#ifdef TARGET_ANDROID
void ofAndroidApplicationInit()
{
    //application scope init
}

void ofAndroidActivityInit()
{
	//activity scope init
	main();
}
#endif

my device: Huawei p20 or Huawei P20 pro with android version 8.1.0 and openframeworks v0.10.0

Ciao
Dario

Start by running the example from ofApp.h, ofApp.cpp, and main.cpp on the reported Android setup, focusing on the fbo.begin(), img.draw(), and fbo.end() sequence. Trace the Android FBO rendering path to determine whether rendering persists without fbo.draw(); done means the behavior is confirmed and either corrected or clearly documented.