Okay this is now getting weird. I tried this config:
mGlView = new GLSurfaceView(this.getApplication());
//mGlView.init(mQCARFlags, translucent, depthSize, stencilSize);
mGlView.setEGLContextClientVersion(2);
mGlView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
mRenderer = new ImageTargetsRenderer(this);
mGlView.setRenderer(mRenderer);
Both in HelloWorld demo and this app. The HelloWorld demo still showed the model perfectly, and the latter one still showed the same problem.
EDIT: while I was posting you replied, so I tried inverting Culling, and disabling/enabling it, to no avail.