compatible; MSIE 6; Win32; Mck IS it a new bot?

User-Agent claimed to be MSIE- with invalid Windows version

Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; Mozilla/4.0(compatible; MSIE 6; Win32; Mck); .NET CLR 1.1.4322; InfoPath.1)

What is this useragent? It first looks ok stating
compatible; MSIE 6.0; Windows NT 5.1;
But then has a second part that which looks like the useragent is starting over.
Mozilla/4.0(compatible; MSIE 6; Win32; Mck); .NET CLR 1.1.4322; InfoPath.1)
Inside this strange string is another browser version.
compatible; MSIE 6; Win32; Mck

What is MSIE 6 This is invalid
What is Win32 this is also a invalid version
What is Mck
Why is Mozilla/4.0 repeated?

If this is not some strange proxy then this is a new bot.

This is banned by BB as a invalid windows version.