Weird error in Airbrake, with UTF8 codes

I've recently encountered an error开发者_JAVA百科 in Airbrake (ex Hoptoad).

The error read

%u672A%u5B9A%u7FA9%u306E%u30A8%u30E9%u30FC%u3067%u3059%u3002

I'm more used to errors like NoMethodError: undefined method '-' for nil:NilClass...

I haven't found a way to convert this to somehing more legible.

Do you know what this means? Should I be worried about that? When I access the same URL, I don't get any error.

thanks!