MediaTypeFormatter Thread safety description on MSDN

Topics: ASP.NET Web API
Sep 19, 2013 at 9:32 AM
MediaTypeFormatter class reference on MSDN has the following information:
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Same for JsonMediaTypeFormatter.

AFAIK, at least ReadFromStreamAsync and WriteToStreamAsync methods are thread safe.

Is this a mistake on the documentation?