Hi,
I can't reproduce this issue in a blank level.

Code:
void resolutionChange () {
	camera->flags &= ~SHOW;
	camPP->flags &= ~SHOW;
	camera->stage = NULL;
	bmap_remove ( camera->bmap );
	camera->bmap = NULL;
	video_mode = video_switch ( video_mode+1, 32, 2 );
	if ( !video_mode )
		video_mode = video_switch ( 1, 32, 2 );
	// wait(1);
	camera->bmap = bmap_createblack ( screen_size.x, screen_size.y, 24 );
	camera->stage = camPP;
	camera->flags |= SHOW;
	camPP->flags |= SHOW;
}