I tried to ask a question about Korean fonts and copied some text directly into the question box. The following image appeared, though I moved the red box beneath the question to make the aspect ratio more attractive. The red box actually appears on the right:
Tried adding, deleting various bits of the Korean text...and StackOverflow always says "Body cannot contain BLAH". I'm assuming this is a bug on SO. Google Translate confirms the text is benign: "Conveyor is not running".