<iframe width="1280" height="720" src="//www.youtube.com/embed/NKvxWMsGW9E?rel=0" frameborder="0" allowfullscreen>blablabla<img src="someimage.gif"></iframe><div>this div is ok</div>
Output for 5.1.0
Fatal error: fatal flex scanner internal error--end of buffer missed in /in/FSksV on line 5
Process exited with code 255.