I build a WCF host and make it work fine(client code generated by SvcUtil, using net.tcp binding).
Until today i found all static int variables return from Host, what should be -1 in fact, but set to 255 in monoDevelop (same codes tested in Visual Studio client and it’s -1).
So I don’t get it, why 255? Is it a bug? or I just did anything stupid? 
I confirmed this is a bug and tested it, but still have no idea how to solve it
Any one got any idea please let me know 
Ty
ref: The most weird bug with WCF - Questions & Answers - Unity Discussions
This bug effect int at [-128,-1], a temp solution is set variables out of this range