Sometimes JS_ErrorFromException returns full source file name not in UTF-8

[dima-lur]

JSErrorReport* pReport = JS_ErrorFromException( cx, excnObject );

Sometimes JS_ErrorFromException returns (possibly) the absolute name of the source file, not the value given in JS::CompileOptions.setFileAndLine. And this value is not in UTF-8 or what?

EDITED: Logged pReport->filename bytes:
99 0 0 0 0 0
Probably a Spider Monkey error