Perhaps filter it out somehow or make it another color, font, size or something so that it stands out more.
There are larger spaces between the lines around the real one, yes, but I think this is a bit too similar and could easily pass if you just eye through and want to know what someone said, not thinking much about it.
The reason that this is a problem while normal links don't necessarily are is that this is a forum feature that should inherently be trusted. For links, people should know to always check where they lead and if you click a link, you know you click a link and you're prepared for it.
Now, there is the feature to tell people they're leaving the domain, but that doesn't necessarily help if you don't think about it but just click past it because you want to see those quotes. You didn't click a link after all, so there should be no problem.
Also, I'm not sure if this intended or not?
But it's totally possible.