What triangle character are you using there in your prompt? Sorry, but I haven't found a way to make it 'stick' to the background before it using any font (at least at 14pt).

Edit: OK, I found the character/theme you are using, but what version of Ubuntu Mono do you have? It won't handle that for me :/

Edit 2: I found a Powerline patched version, but that doesn't seem to work either… Maybe I will just switch back to Consolas